340 EDITORIAL ARTICLE.

days. In one of the untreated (No. 22) the piroplasms disappeared on' the fourth day of the reaction, and reappeared on the eleventh day. In the other they persisted until the fifteenth day.

Presence of Blood Clzanges.-These were present in one of the three treated and in one of the two untreated.

The observations in Series III. furnish further evidence that the action of the drug is to confine the piroplasms for a time to the internal organs. It certainly does not appear to clear them com­pletely out of the system, since they reappeared after an interval, as in the case of some of the untreated. Had the piroplasms not reappeared after treatment it was intended to test the virulence of the blood on another animal. I think there can be no reason to doubt, however, that the blood of an animal treated with trypanblue retains its virulence and can infect ticks, but on this point I hope at a future date to furnish further information.

Tile Actual Problem in Practice.-The demand in infected colonies is not so much for a remedy as for a preventive. The cattle in most cases wander over very extensive pastures, and might be very ill before they were observed, or they might never be noticed. Remedial measures can only be applied in the case of animals on a home farm or under cover, but, of course, there are many such both at home and abroad which run on infected pastures. Still, the fact remains that the necessity for treatment is seldom apparent until red water is being passed, that is to say, after the animal has been more or less severely damaged, and it is a question whether prevention of an acute attack by salting is not the preferable method of dealing with redwater, except in those cases in which eradication of infected ticks from the pastures seems a practicable proposition. It is possible, how­ever, that trypanblue may help to make the process of immunisation more regularly mild.

I think the experiments described in this article support the con­clusion of Nuttall and Hadwen that trypan blue has a marked effect on the bovine piroplasm-at least, I think, 011 those in the blood stream.

I do not think, however, that the advantages and disadvantages of the drug can ever be properly assessed by experiments carried out in the laboratory, but that these points must be decided by prac­titioners after extensive trials in the field.

E D ITO R I A L ART I C L E.

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MILK-BORNE SCARLET FEVER.

THE report by Dr W. H. Hamer and Dr T. Henry Jones which is published at a later part of this number raises (p. 363) once more a question which the majority of people had thought to be settled,

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viz., whether an outbreak of scarlatina may be caused, not by infec­tion of the milk through human agency, but by milk which derives its infective properties from the cow herself.

As is well known, the contention that scarlet fever is a natural disease of the cow was first put seriously forward in connection with the famous Hendon outbreak in 1885. The controversy which raged round the etiology of that outbreak gradually died down without conducting to anything like unanimity concerning the possible occurrence of scarlet fever in the cow. It must, however, have been felt by the disputants on both sides that time was bound to settle the matter, and place the occurrence of scarlatina in the cow beyond the possibility of doubt or denial, provided the cow were really susceptible to that disease. Such an expecta­tion was justifiable, because it was obvious that there must be numerous opportunities for the transmission of the disease from man to the cow, and that among the future outbreaks of human scarlet fever caused by the milk of diseased cows there would surely be some in which the circumstantial evidence would be so clear as to compel conviction. Conversely, it must have been felt that if the future failed to provide such cases it would be reasonable to regard the Hendon outbreak as one in which a human source of infection had been in existence but had been overlooked.

The lapse of time unquestionably served to strengthen the position of those who had from the first denied the existence of such a disease as cow-scarlatina, for it failed to bring to light any milk-borne epidemic in which the evidence to incriminate the cow was more convincing than it was in the Hendon case. In consequence, the alleged cow-scarlatina has failed to establish a place for itself in veterinary pathology, and, except among medical officers of health in Great Britain, belief in the occurrence of such a source of human outbreaks has within recent years steadily lost ground.

But history has many examples to show that an important truth may have to wait a long time for general acceptance, and the fact that belief in the occurrence of cow-scarlatina has within recent years been steadily declining ought not to be allowed to prejudice what purports to be fresh evidence in support of that belief. Such evidence. especially when it is put forward by persons of acknow­ledged authority, is deserving of careful consideration, and that is what we propose to accord to the recent report by Drs Hamer and Henry Jones.

In the first place, it is right that a tribute should be paid to the • masterly manner in which the authors, in circumstances that must at first have appeared very unpromising, succeeded in tracking down the infection to a single farm, viz., the one which is termed X in the

34 2 EDITORIAL ARTICLE.

report. In consequence of this success it was possible to stop the infection at its source, but, unfortunately, not before upwards of 400 persons had contracted an attack of scarlet fever through drinking the contaminated milk. Noone who reads the report carefully can entertain any doubt that the milk supplied from this farm, X, was the actual cause of the epidemic.

So far, therefore, the report is plain sailing, but, unfortunately, room for difference of opinion arises as soon as an attempt is made to proceed further and show what was the precise source of infection at the farm.

The authors of the report paid their first visit to Farm X on Sunday, 20th June, or six days after the first cases attributed to milk infection had been reported. Previously it had been reported to them that there were some cases of German measles at the cottage of a man employed on this farm, but what they found on arrival was that this man, his wife, and their three children were all suffering from scarlet fever. One of these children had been ill since the 11th, and the father had been ill and off work since the 15 tho

Farm X, it ought here to be noticed, comprised two separate steadings (Xl and X2) some distance apart, each with a lot of cows, and the man who has just been mentioned (G. L.) was employed to cart the milk from both lots of cows to the depot of a milk company. He generally acted as an auxiliary milker at one of the places (X2), and occasionally also at the other (Xl).

No human source for the infection of this man's family could be traced, but it was ascertained that he had an allowance of one pint of milk daily from the farm, and this, it is said, was generally taken by the family with tea, but was occasionally drunk raw by the children. The report omits to state whether this milk was supplied from Xl or X2.

The discovery of these cases of scarlet fever on Farm X of course raised the question whether the man G. L. was or was not the source from which the milk became contaminated. The authors of the report, after mature deliberation, pronounce against this explanation of the epidemic, and it is important to note their reason for so doing. It is that the milk had caused infection among consumers in Surrey "at least four days before the appearance of symptoms of illness in any member of the milker's family." The conclusion is therefore drawn that" the milk infected the milker and not the milker the milk."

The first criticism which suggests itself with regard to this part of the report is that it is not a little remarkable that the authors apparently do not attribute any of the 400 cases which cOf!stituted the epidemic in the county of Surrey and in London to the agency

EDITORIA L ARTICI.E.

of this mall, G. L. To most people this will appear strange when it is remembered that the man continued to milk cows for four days after one of his children had sickened with scarlet fever, viz., from the I rth to the 14th June, both inclusive. And the omission is the more striking when it is further recalled that, as far as can be gathered from the report, the first of the reported cases which are attributed to thc milk wcre notified on the 14th June. We have italicised the word " reported," to show that we have not overlooked the fact that the authors were subsequently informed that, although in one district the earliest cases were notified on the 10th June, the doctor who notified nearly all the cases said that he had "several cases of sore throat during the week previous, not followed by rash and not notified." The cases here referred to are those which occurred among the customers of the vendor, A., and it will be observed that, on the strength of this information, the authors in the Chart which they have constructed ('see p. 367), fix the 9th June as the date of commencement of illness in patients supplied by this vendor. Among the cases which occurred among the customers of all the other vendors of milk from Farm X, according to the Chart, none commenced earlier than the 10th June, and, as previously mentioned, it would appear that cases assigned tv the epidemic were first notified on the 14th June.

I n order to be able to form all opinion as to whether the milker. G. L., was the fountainhead of the infection one would require to be supplied with precise information showing (r) the date of the first case in each district in which the milk from Farm X was distributed, and (2) the date of the last case attributable to the consumption of this milk. As we have just indicated, the date (9th June) assigned to the first of these by the authors cannot be accepted without reserve, for" cases of sore throat not followed by rash" may not have been cases of scarlet fever at all. As to the second point the report supplies no precise information, and this is very unfortunate, for had it been provided it probably would have proved conclusively whether there was any source of the milk infection outside the family of G. L. or not. In lamenting this omission we are not forgetful of the fact that it probably would have been difficult, and perhaps impos­sible, to ascertain the exact date of the last case caused directly by consumption of the contaminated milk, but a careful tabulation of the date of onset of the symptoms in each reported case among the milk consumers who were not known to have been exposed to risk of human infection could not have failed to furnish valuable evidence for or against the view that G. L. was the main or exclusive source of the milk-borne epidemic. A fact which has the greatest signifi­cance in this connection is that, as is admitted in the report," 14th June

344 EDITORIAL ARTICLE.

was the day on which the milk did most mischief," for that was the last day on which G. L. milked any of the cows. This is quite con­sistent with the view that G. L. was the source of the mischief, but he had nothing to do with the milk after the evening of the 14th June, and any infection derived from him was presumably cut off at the places where the milk was distributed on the evening of the 15th. The importance of this becomes obvious when it is taken in con­junction with the further fact that the milk from Farm X continued to be sent out until the evening of the 18th June, and that milk of the 16th caused no infection among the customers of vendor M.

We may here notice a point which offers a certain difficulty whether one ascribes the contamination of the milk to G. L. or sets it down to direct cow infection. It is that no cases could with certainty be traced to the milk sent out from Farm X on the 11th and 12th. The explanation of this fact which the authors of the report suggest is that on these days the vendors among whose customers the milk caused no mischief happened not to receive milk from any of the diseased cows. But another explanation which is at least as probable is that on the 11th and 12th G. L., who was only an auxiliary milker, did not milk any of the cows, or at least did not milk any at one of the farms, and, in the latter case, that the milk which failed to infect was derived from the lot of cows in the milking of which he had taken no part.

\Vith reference to this question of the date at which the milk from Farm X ceased to be infective, the report contains one remarkable paragraph. The authors state that it was not possible to say exactly when the milk ceased to be infective, but go on to suggest that it was still dangerous. for three or four weeks after the 18th June. And what is the evidence on which this suggestion is made? It is that several weeks after the epidemic had come to an end in Surrey and London illness was developed in the family of the milker at Farmstead X~, and that the reported symptoms "suggested" scarlet fever! Although it was obviously of the utmost importance to determine whether the illness was really scarlet fever or not, apparently no steps to that end were taken, and the only information supplied is that the nature of the illness was still in doubt when Mr Dunbar, the County Council's Veterinary Surgeon, visited the farm on the 26th July. And then follows the curious statement that ., if this illness was caused by drinking milk the milk must have remained infective for five or six weeks, dating from 7th June." It is obviously impossible to assent to that statement if the words "remained infective" are intended to mean that the milk during all this period was capable of causing scarlet fever in persons consuming it. All that the authors were entitled to say in this connection was that tf tlte illness

EDITORIAL ARtICLE. 345

in tile .faJlli~J' (i.f tltl' lIlilker at Firnllstcad "\~2 was sc,wlet .fe'uer, and if it was caused by drinking the milk, the milk was iafective at some elate later than r8th June-a statement which is an obvious truism, but devoid of any force when the point under discussion is whether the milk at any time contained the germs of scarlet fever derived from diseased cows.

But this reference to the occurrence of some undiagnosed illness in the family of the milker at Farmstead X2 raises another question. In an earlier part of the report it is stated that the family of this milker included his wife and her mother, and six children, and that no case of scarlet fever had occurred in the household up to the 20th June. It is, however, !lot stated whether this milker, like G. L., was allowed a pint of milk a day. If he was, the fact is a material one and ought to have been mentioned, for if the cases in G. L.'s family were caused by this daily pint of milk it is rather remarkable that the six children at a susceptible age in the other family should have escaped at the time when the milk had its maximum degree of infectivity. If, on the other hand, no milk was supplied to this second family, there was no ground for suggesting that the obscure illness which began in July was scarlet fever derived from the cows.

To the reasoning in the preceding paragraph it might be objected that the escape of the family of the milker at Farmstead X2 while the epidemic wa<; at its height is just as inexplicable on the one theory as on the other, but a little consideration will show that that is not correct. G. L. had nothing to do with the mixing of the milk, and, assuming that he was the sole cause of the epidemic, the only milk infected as it left the farm would be in the churns containing the milk of cows milked by him. As at most he milked only two cows at each farmstead, the chances are greatly ill favour of the view that any milk supplied to the milker at Farmstead X2 would be milk not contaminated by G. L. The theory that G. L. was the fountain­head of the infection is thus in perfect harmony with the fact that at Farmstead Xl the farmer, his wife and her sister, and the foreman milker, and at Farmstead X2 the milker, and his family of eight persons, all escaped the diease, whereas the escape of all these persons is very difficult to explain if it is maintained that the cow disea'3e discovered at both farmsteads was the source of the infection.

To sum up our criticism of this part of the report, we may say that in our opinion the ascertained facts do not in the least justify the conclusion that the milk infection was not derived from a human source. It is true that no human source for the infection of G. L. and his family was discovered, but the authors of the report are debarred from attaching any great importance to that fact, for, as will presently be shown, they also failed to trace any antecedent

EDI'lORl~L .\RTICLE.

case, whether human or bovine, to account for the infection of the cows with scarlet fever.

Having given our rea'ions for maintaining that the authors of the report have failed to prove their first contention, Yiz., that the epidemic had not a human source, we haye next to deal with the evidence adduced in the report to prove that the cows at Farm X were the fountainhead of the infection.

The authors having decided (r 1 that there was 110 human source for the epidemic, and (2) that the milk first became infective about the 7th June, had to find some conciition affecting the cows which first came into operation about that date After a good deal of trouble they were able to satisfy themselves that about that time the milk of three heifers was for the first tim~ added to the general supply, and apparently because one of these unfortunate beasts lost her calf when it was four or five days old it is suggested that this was the particular animal with which the scarlet fever infection originated.

It cannot be too strongly insisted, however, that the authors do not offer any evidence whatever to prove that the outbreak among the cows had not been in existence long bt:fore the 7th June. They a(imit that they were not able to obtain any information with regard to this point, and no other conclusion is possible than that such information was deliberately withheld by those who had to milk and look after the cows.

In spite of this absence of precise information, the authors attempt to determine not only the approximate date when the disease broke out but also the animal first attacked. What evidence is put forward to show that this was the red heifer? N one whatever, except the absolutely doubtful suggestion that this animal's milk was first added to the general stock on the 7th June. And if any one will read the report carefully he will see that this date is contra­indicated by the information obtained from the milkers, which was that the red heifer calved about the 24th May. and lost her calf four or five days later. That would mean that her milk was first used a week earlier than the date suggested by the authors, which would be fatal to the contention that this animal's milk started the epidemic, if that began on the 7th June.

But the authors have evidently ignored a consideration which makes it almost impossible to conclude that the red heifer was the first to be attacked, if one accepts the statement that her calf died four or five days after birth and the suggestion that her milk was first used on the 7th June. This would imply that the heifer calved about the 2nd or 3rd of June, and that she had developed an erup­tion on the udder or teats before site Itad been milked, although it is admitted that this did not happen in any of the other cases. The

EDITORIAL ARTICLE. 347

practice apparently was to leave the calves with their dams for about a fortnight after calving and not to milk them during this period. Thus, one finds it stated in the report that when the farm was inspected on the 21st June two cows which had calved a fortnight previously had not yet been milked, and both had healthy teats and udders.

The case against the red heifer having thus fallen to the ground , and the suggested coincidence of the cow eruption with thc com­mencemcnt of the epidemic being entirely unsupported, it remains to examine the other grounds on which the public are asked to accept this outbreak as one in which the infection was derived from a bovine source. As a matter of fact, it requires considerable study to find in the report anything further that can properly be called evidence in support of the authors' main contention. Nothing remains except that the majority of the milch co\\'s at Farm X had lesions on their udders or teats, C'the conditions being similar to those first described in 1885 at a Hendon farm."

The authors are to be commended for their cautious choice of words in the only description that they have condescended to give of this eruption. It was" similar" to that which was present on the udders and teats of the Hendon cows! Alas, this is not very helpful, for there is nowhere to be found a description which enables anyone to diagnose the" Hendon disease" in the absence of proof that it has caused scarlet fever in persons consuming the milk, or to distinguish between it and other eruptive conditions which any day of the year can be shown to be present on the udders or teats of cows whose milk is quite innocuous.

The authors of the report evidently do not possess the necessary knowledge for such discrimination, for otherwise their language would not have been so guarded. Mr Dunbar, the County Council's veterinary surgeon, labours under a similar disability, for he confines himself to recording the presence of "scars," c'scabs," "vesicles," " pustules," and" excoriations," and is confident of nothing save that the disease was not cowpox. But the case would have stood in exactly the same position if all these gentlemen had with one accord declared that the lesions on the cows at Farm X were identical with those present on the Hendon cows, for the simple reason that in that famous case the connection between the cow disease and the concurrent scarlet fever epidemic was no more proved than in the present instance.

And now we come to the question of the origin of the scarlet fever among the cows. We say" scarlet fever," because if the cow disease caused scarlet fever in man we do not see why the authors should boggle at the name or prefer to speak about it as one which invested the milk with" a special pathogenic quality . . . which produced scarlet fever among consumers."

l!.D1TO RIAI. ARTICLE.

It is impossible not to sympathise with the authors in the desperate a rgumentative straits to which they are reduced when they, as part of their theory, have to show how the disease was introduced to Farm X. They were debarred from suggesting that it had originated de novo, for if scarlet fever can originate in the cow it may also originate in man, and might have originated in the milker, G. L., or any of his family. They were also debarred from suggesting that it was brought on to the farm with the last purchased cow, for that animal was 'bought in March, and the milk was not infective till June. As a last desperate guess the a uthors suggest that it may have been introduced with the feeding cake, especially since th e dry cows got no cake and developed no eruption on their t eats ! To state reasons for not accepting this suggestion would be to do it an honour to which it is not entitled.

In fairness to the authors of the report it ought to be admitted that they do not anywhere represent the conclusions a s to the source of the outbreak which they are inclined to draw as ascertained and demonstrated truths. The view which they have adopted is put forward as the one which afford s the best explanation of the fact that during a certain period in the month of June last the milk from Farm X contained the virus of scarlet fever. That view is that the germs of scarlet fever were introduced into the system of a particular animal (a red heifer) on that farm, probably in some food material, and that in consequence of such infection the milk of this animal, and of others similarly a ffected at a later date, contained the virus of the disease and conveyed it to the consumers.

An alternative explanation i s that the milker, G. L. , was the sole ')ource of the milk contamination, and that the scarlet fever in his famil y originated from some human source which was not traced.

The second suggested expla nation requires assent to only one unproved possibility, vi z., that a human source for the infection of G. L.'s family may have existed, although the inquiry failed to discover it. , The explanation put forward in the report requires previous assent

to several things which are not nnly unproved but highly improbable. Most of these improbabilities have already been n oticed , but the g reatest of them is that the disease of human beir, gs which is termed scarlet fever is communicable to cows, and is manifested by an e ruption on the udder and teats.

W e leave our readers to make their cho ice be tween these two theories, observing merely th at when there are alternative explana­ti ons of any natural phenomenon it is philosophically unsound to reject the simpler one.