BACTERIOLOGICAL REVIEWS, Sept. 1973, p. 284-288Copyright 0 1973 American Society for Microbiology

Vol. 37, No. 3Printed in U.S.A.

Agostino Bassi Bicentennial (1773-1973)J. R. PORTER

Department of Microbiology, University of Iowa, Iowa City, Iowa 52242

Agostino Bassi (Fig. 1) was a most curiousand ingenious naturalist who first establishedthe doctrine of microbial parasitism and whopostulated theories on, or worked in, manyother important areas of agriculture, scienceand medicine (3, 4, 8, 11, 12). His observationsand great contributions to these fields are notfully appreciated by most scientists today.

Little is known about the early life of Bassiother than that his parents (Rosa Sommarivaand Onorato) were farmers and that he wasborn as a twin (his brother was GiovanniFrancesco) on 25 September 1773 in the villageof Mairago near Lodi, Italy. After completinghis first schooling at the local gymnasium hewent to the University of Pavia where hestudied law to satisfy the wishes of his parents;he received his doctorate in law on 21 May 1798.For his own interests, however, he also tookcourses in chemistry, physics, mathematics,natural history, and certain topics in medicine.His teachers were such distinguished men asSpallanzani (physiology), Scarpa (anatomy),Volta (physics), and Rasori (physiology). Theclassical studies of Spallanzani on disprovingthe theory of spontaneous generation of micro-organisms were in vogue at the time, and theyundoubtedly had a great influence on the think-ing of Bassi.When Bassi returned home after graduation

from university he was appointed provincialAdministrator and Assessor of Police in Lodi.Later, he was admitted to the Electoral Collegeof Scholars in the district and became theChancellor of the Census Delegation. With thisrecognition he was soon offered positions inother cities, but he preferred to remain in Lodiwith his parents and friends.Owing to his extensive reading and the de-

tailed bookwork that his position required, hiseyesight began to fail. Thus, about 1816 hedecided to abandon his public posts and literarywork and devote full time to agriculture. He hadalready acquired at great expense a few Merinosheep, which he decided to raise for their finewool. He increased his flock through carefulselective breeding to over 400 animals, buteventually the price of wool dropped so drasti-cally that he had to sell his sheep for meat.

During this experience Bassi published (12) hisfirst book, The Well-Instructed Shepherd,which received much praise because it con-tained several novel ideas such as how to selectewes that might bear twins and how to identifyindividual sheep by numbers.

In 1817 Bassi completed a small treatise Onthe Usefulness of the Potato and the Best Wayof Cultivating It, which was well received be-cause it described simple plans for planting,avoiding diseases, and harvesting the tuber.About this same time a famous chemist andProfessor of Agriculture, Giovanni A. Giobert,in Torino published a pamphlet on a new way offertilizing land without the use of manure.Count Carlo Verri of Milan and Bassi opposedthe method; in fact, Bassi carried out experi-ments and published (12) a critical review,Observations by Doctor Agostino Bassi on theExcessive New System of Fertilizing Pro-pounded by Signor Professor Gio. A. Giobert.This pamphlet was reprinted in newspapers andperiodicals in the region. Bassi's agriculturalexperiments were conducted on several farmsaround Lodi; one that he owned became knownas "the potato field", and another that herented was later named La Bassiana in hishonor.When a cheese factory was built in the area,

Doctor Bassi wrote an authoritative scientificdissertation on the subject, which was pub-lished (12) in both Milan and Lodi in 1820. Henot only offered a theory on cheese manufac-ture, but indicated the best way to cure andstore it after production. Cheese makers whofollowed his suggestions produced the bestcheese in the Kingdom of Lombardy, and itbecame known as the superior Lodigian Cheese.About this same time various publications

began to appear in France and Italy on themethods of making wines in covered vats thatwere dated to indicate the value of aging. Thesepublications prompted Bassi to write up his oldpractices on the making of wines and to proposenew methods and instruments in treatises (12),Comments on New Methods of Making Wine(1823, 1825). These works received much praisein public papers and encyclopedias, such asBiblioteca Italiana (32:84, 1824, and 35:359,

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AGOSTINO BASSI BICENTENNIAL

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FIG. 1. Agostino Bassi (25 September 1773 to 8February 1856). The decorations are the Legion ofHonor and the Medallion of Civil Merit for his work onmuscardine. His motto was "When the fact speaksreason remain silent, because judgment is the daugh-ter of fact, not fact the son of reason" (8, 12).

1825). Bassi was not only an expert on makingwine from grapes, but from other fruits as well,a practice that was previously unknown. Themost distinguished of these, because of theirflavor and aroma, were made from the Morellocherry and the orange. Somewhat later one ofBassi's friends, Court Verri, wrote extensivelyabout wines and vines. Because of his respectfor truth and science, Bassi prepared a criticalanalysis of the work pointing out errors.Since silk was one of the major products of

Italy, several persons were writing on how toraise silkworms and grow mulberry trees. Butup until the time of Bassi no one in Italy,France, or elsewhere knew how to deal with thegreat loss of silkworms caused by a disease

called calcinaccio, calcinetto, calcino, or mus-cardine. Beginning about 1807 and continuingfor over 30 years, Bassi carried out an extensiveseries of controlled studies on breeding silk-worms, environmental tests, microscope obser-vations of healthy and sick worms, and fieldtrials for developing new types of the mulberrytree. After much labor and expense, he discov-ered the nature of the disease as well as methodsfor its prevention and cure. Near the end ofthese studies Bassi was having financial trou-bles so he kept his results secret with the hope ofselling them at a fair price. They were offeredfor sale, but since no one made him an offer,silkworm cultivators had to wait several yearsbefore they were able to benefit from his greatdiscoveries. Finally, tired of keeping such mat-ters of vital importance to himself and placingthe good of the public before his own, Bassi lethis results become public through a demonstra-tion at the University of Pavia in 1834 and intwo monographs published (3, 4) in 1835 and1836 which he called On the Disease of the Sign.Calcification or Muscardine, a Disease thatAfflicts Silkworms. Part I. Theorv; Part II:Practice.

Bassi's monographs revealed that the first 8years of experimentation on silkworm diseasefailed because he tried to prove two popularassumptions: (i) that the disease developedspontaneously from the environment (atmos-phere, food, method of breeding), and (ii) thatthe tissues of the silkworm were transformedinto a liquid by hyperacidity of the insects. Inspite of many well-controlled experiments,Bassi could not prove these assumptions, and hebecame discouraged and depressed with hiswork about 1816. He had almost discontinuedhis studies when he noted that before the illnesscould develop, a foreign agent had to enter theworm from outside. He therefore set about todiscover the nature of the agent, its habits, theways by which it entered the silkworm nurser-ies, and, if possible, the means of preventing orcuring the disease.

Bassi found that the infectious agent wasrelated to the white (calcino) efflorescence thatdeveloped on dead silkworms, and that whenthis material was introduced on the point of aneedle into healthy silkworms of any stage(caterpillar, pupa, moth) it sprouted, grew,killed and mummified the worms, and producedfruits (spores). He noted that some silkwormsare diseased but never turn white, their conta-gious properties being inside the worm. In everycase, however, he observed that death was dueto the blockage of circulation of the lymph

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caused by the growth of the parasite. Also hedemonstrated that the agent was organic, liv-ing, and of vegetable nature: a plant of the typeof the crytogames. When observed under themicroscope (Fig. 2), the infectious agent ap-peared to be a fungus similar to Botrytisparadoxa (4).

Intuitively, he had a clear idea that thefungus caused the disease, and he concludedthat death resulted from the reproduction of thefungus and not otherwise. Thus, for the firsttime, a human being formulated the parasitetheory of disease. Bassi, however, did not iden-tify the fungus completely; it was later charac-terized and named Botrytis bassiana in hishonor by Balsamo-Crivellis and then trans-ferred to the genus Beauveria by Vuillemin (13).

Bassi's practical monograph (4), and a subse-quent second augmented edition published in1837, was concerned mainly with measures forpreventing and curing the disease. The workwas logically based on the theories and charac-teristics of the fungus mentioned in the firstmonograph (3). He demonstrated that to pre-vent the disease, silkworm eggs should be disin-fected with dilute solutions of calcium chloride,alcohols, or nitric acid. When eggs were pur-chased from outside sources the containersshould be disinfected or burned. Fresh, uncon-taminated mulberry leaves should be used forfeeding silkworms. All instruments and imple-ments used in the nursery should be disinfectedin boiling water or exposure to fire. The nurseryshould be well ventilated, flies should be keptout, crowded conditions should be avoided, andin a dry season the floor should be sprinkledwith water to keep down the dust. Workersshould practice hygienic measures.

Should muscardine develop in a nursery,special precautions should be taken immedi-ately. All diseased silkworms should be de-stroyed, and instruments, trays, tables, androoms should be disinfected. Workers shouldwear protective clothing that could be boiled,and they should wash their hands after havingcontact with diseased insects.Even though Bassi's studies satisfied his

motto that "fact speaks reason", the resultswere criticized by many learned persons of theday who continued to believe in the spontane-ous generation of microorganisms. Thus, to gainsupport for his parasitic theory of disease and tosave the silk industry, he decided in 1833 tosubmit his work for adjudication by the Univer-sity of Pavia. The following events (6, 9) oc-curred (Fig. 3):"Signor Doctor Bassi of Lodi in 1833 applied to the

Imperial Royal University of Pavia for permission to

communicate some of his experiments and findings onthe disease of the silkworm called il segno. Butbecause during that year the appropriate experimentscould not take place, he renewed his applicationduring the current year, 1834. He conducted theexperiments in the presence of a Commission com-posed of members of the faculties of Medicine andPhilosophy, which reached the following conclusions:

1.° The white substance, crust, or efflorescence onthe silkworm is indeed infectious, and hence placed incontact with a healthy insect will transmit andpropagate the disease.

2.0 The efficacy of this substance can be destroyedby various chemical agents which do not damage theinsect. This can be done before the said substance isbrought into contact with the insect or after, providedthe remedy is applied soon after contamination.

3.° In view of the extreme ease with which thisinfectious substance spreads, and adheres to every-thing firmly; and considering the minute size of itsparticles in consequence of which a single dead wormwhen reduced to the state of efflorescence can infect awhole silkworm nursery, it cannot be doubted that thesaid substance is the usual cause of the mentioneddisease.

4.° Seeing that there are chemical agents that candecompose and destroy the infectious substance, theCommission declares its conviction that by the properuse of these agents the all too easy transmission of thedisease can be stopped and the disease cured andprevented."

"Pavia.. . Configliachi, Pro-Director of PhilosophicalStudies and Professor of Physics,

Moretti, Professor of Agrarian Science and Botany,Brugnatelli, Professor of General Natural History,Pinali, Pro-Director of Medical Studies,Dr. Pietro Carpanelli, Dean of the Faculty of Medi-

cine,Dr. Gia. B. Laurin, Professor of Veterinary Science,Platner, Professor of Medical Police,De Cattanei di Momo, Temporary Professor of Chem-

istry,Giammaria Zendrini, Professor of Special Natural

History."

"I certify the signatures and titles of the abovelisted professors as authentic: Drs. Pietra Configlia-chi, Ordinary Professor of Physics; Moretti, OrdinaryProfessor of Botany and Temporary Professor ofAgriculture; I = *; Pinali, Pro-Director of MedicalStudies; Pietro Carpanelli, Dean of the Faculty ofMedicine; Dr. Gia. Batt. Laurin, Professor of Veteri-nary Science; Platner, Professor of Medical Police; DeCattanei di Momo, Temporary Professor of Chemis-try; Giammaria Zendrini, Professor of Special Natu-ral History, In this I.R. University, Pavia on 30August 1834.

Dr. Cesare Ripari, Registrar"*1 = Brugnatelli, Professor of General Natural History

After his successful demonstration at theUniversity, Bassi was issued a certificate con-

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FIG. 2. Amici microscope supposedly used byBassi and now in a museum in Lodi (6, 9, 10). InChapter VIII of Bassi's monograph (3), he urgedscientists of Florence, indeed De Amici himself, tolook at the muscardine germ with his very powerfulmicroscope; hopefully, with this unique instrumentone might detect the shape and true nature of theparasite.

firming his work, which he printed in thepreface of his first monograph (3).

In 1838 Bassi inherited a considerable sum ofmoney from a cousin, Count Luigi Sommariva,and his financial condition became sufficientlysecure so that he could devote himself entirelyto his studies. But he held money in very lowesteem and always supplied funds and medicineto the poor. Professor Riquire stated (12) "who-ever came to Bassi, whether it was for help or a

loan, never left empty-handed".Because of his poor eyesight it is questionable

whether Bassi did any microscope work after1837, but he continued to develop his theory ofcontagion from iiving parasites. From 1844 to1853 he published several papers (12) on conta-gions in general, especially those that afflicthuman beings. He applied his theory to suchdiseases as smallpox, typhus fever, plague,rabies, gonorrhoea, syphilis, cholera, and gan-

grenous wounds. For example, in his 1849 paperon preventing and curing Asiatic cholera (12) hedeclared that the cholera germ was more minuteand slender than the fungus responsible formuscardine, but that it was a cryptogame. Oneshould appreciate that this idea was expressed34 years before Koch isolated the cholera vibrio.Bassi advocated strict quarantine for patientswith certain diseases such as cholera, and statedthat contaminated eating utensils and bed linenshould be boiled to destroy the infectiousagents.

In one study he turned his attention topellagra. He was unable to apply his parasitetheory to this disease, and he of course knewnothing about vitamins, but he was able todemonstrate (12) that corn in the diet of humanbeings was not the cause. He also wrote exten-sively on the application of heat for steriliza-tion, and the use of disinfectants such asalcohol, acids, alkalies, sulfur, and chlorine. Invaccinating children in series for smallpox, hestrongly advocated the necessity of sterilizingthe needle between each vaccination so as toavoid complications or the transfer of otherdiseases. Bassi continued to publish significantarticles until 3 years before his death at age 83on 8 February 1856 (7).

Bassi belonged to several Italian and foreignscientific academies; in the library at Lodi, 14 orso diplomas and nominations are preserved. Hewas presented gold and silver medals by thesovereigns of several nations, but he reportedlyhad some of these melted to provide financialaid to his friends and the poor. He was made aCavalier of the Royal Order of the Legion ofHonor, of which one became a member onlythrough superior authorization. Since his deathhe has been honored on several occasions inItaly (6, 8, 11).One cannot read (1-12) about Cavalier Doc-

tor Agostino Bassi without realizing that he wasa great pioneer in the development of knowledgedealing with the cause and prevention of infec-tious diseases, as well as a person who contrib-uted unique ideas to others working in diversefields. His writings directed many people toconsider microorganisms as the cause of bothanimal and plant diseases. For example, in 1839J. L. Schoenlein gives Bassi credit for hisdiscovery of the fungus responsible for ring-worm, and others, including Pasteur, men-tioned his work in their writings (2, 6, 8, 10, 11).Several distinguished Italians, medical histori-ans, and editors of journals (see 2, 10) havealways maintained that Bassi was the founderof the parasite theory of disease and thereforerightfully should receive more credit for the

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FIG. 3. Signed certificate issued by the archivist of the University of Pavia, 30 August 1834, to verify Bassi'sexperiments on silkworm disease (3, 4, 6, 9. 11).

later discoveries by Schwann, Semmelweiss,Pasteur, Koch, and Lister. As is the case withmany other persons who make great discoveries,however, Bassi was unable to add the final proofto most of the theories he postulated. Undoubt-edly, he first proposed the germ theory ofdisease, but, possibly because of his poor eye-sight, he was unable to observe by microscopydetailed features of the fungus, cultivate it,characterize it, or implicate it definitely as thecausative agent of the silkworm disease muscar-dine. As stated by Major (10), "the proof of hisassertions was discovered by his successors andupon them the world has bestowed its honors."Because of Agostino Bassi's outstanding contri-butions to our knowledge on many topics,however, he should be recognized and honoredon his 200th birthday in a manner fitting a greatperson in history (2, 6, 8, 11). A commemora-tive program will be held for him in Lodi, Italy,27 to 29 September under the supervision ofthe Societa Italiana di Medicina Veterinaria.

LITERATURE CITED

1. Ainsworth, G. C. 1956. Agostino Bassi, 1773-1856.Nature (London) 177:255-257.

2. Arcieri, G. P. 1956. Agostino Bassi in the historyof medical thought. A. Bassi and L. Pasteur, p.40, Olschki, Florence.

3. Bassi, A. 1835. Del mal del segno, calcinaccio omoscardino, malattia che affigge i bachi daseta, e sul modo di liberarne le bigattaje anchele piui infestate. Parte prima: della teoria, p. 64.Tipografia Orcesi, Lodi.

4. Bassi, A. 1836. Del mal del segno e di altremalattie dei bachi da seta. Parte seconda.Practica, p. 58. Tipografia Orcesi, Lodi.

5. Bassi, A. (P. J. Yurrow, trans.) 1958. Del mel delsegno, p. 49. Phytopathological Classic, no. 10,American Phytopathological Society. Monu-mental Printing Co., Baltimore.

6. Belloni, L. 1956. Documenti Bassiani. I.G.I.S.,Milano.

7. Belloni, L. 1969. Le "contagium vivum" avantPasteur. D74, p. 35. Universit6 de Paris.

8. Belloni, L., L. Vergnano, and A. Zambianchi.1956. Studi su A. Bassi, p. 109. Archivio StoricoLodigiano, Lodi, Italy.

9. Corti, A. 1959. Facts, times and names never to beforgotten. Sci. Med. Italica 8:107-146.

10. Major, R. H. 1944. Agostino Bassi and the para-sitic theory of disease. Bull. Hist. Med.16:97-107.

11. Societh Italiana di Storia della Medicine. 1956.Agostino Bassi nel primo centenario dellamorte, p. 49. Fausto Capriotti, Roma.

12. Societa Medico Chirurgica di Pavia. 1925. Operedi Agostino Bassi, p. 673 and lxviii. TapografiaCooperativa di Pavia.

13. Vuillemin, P. 1912. Beauveria, nouveau genre deVerticilliacbes. Bull. Soc. Bot. Fr. 59:34-40.

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