THE HISTORY OF BACTERIOLOGY. 53 



scarlet fever seed or germ — a. seed which could never give 

 rise to smallpox. He showed that it was possible for this 

 organism to become disseminated through the air, and for it 

 to multiply in the body ; and .he explained the incubation 

 stage of a febrile disease as dependent on the growth of a 

 germ within the body during the period after its introduc- 

 tion, when its presence had not yet been made manifest. He 

 very rationally explained the differences in the character of 

 the symptoms and the severity of the same disease by refer- 

 ring them to differences in the constitutions and surround- 

 ings of the patients. As regards putrefaction, having 

 corroborated Linnaeus' observations and found countless 

 animalculae in putrefying matter, he came to the conclusion 

 that this process was the result of the development, 

 multiplication, and carrying on of the functions of nutri- 

 tion and excretion by these germs ; the products of 

 fermentation being the volatile salts set free by the organ- 

 isms, which, multiplying rapidly by forming seeds or eggs, 

 rendered the fluid in which they developed thick, turbid, 

 and foul. This theory, admirable as it was, and accurate as 

 it has since been proved to be, could not then be based on 

 any very extensive or detailed observation, and we find that 

 some of the most prominent and brilliant men of the 

 period did not feel justified in accepting the explanation that 

 Plenciz had offered as to the causes of disease and fermenta- 

 tion processes; and it was not until the years following 1831 

 that any real advance could be made in our knowledge of 

 the presence of a " Contagium vivum," or living contagium 

 element in the production of disease and fermentation. 

 Previous to this, however, there was being gradually 

 accumulated a large mass of facts bearing on these wonder- 

 fully interesting minute living organisms, and numerous 

 isolated observations were constantly being made by various 

 workers, none of whom, however, were sufficiently master 

 of their subject to enable them to make any systematic 

 attempt at classification of their accumulated facts, and the 

 scientific results were consequently comparatively small, 

 standing in no proportion to the amount of work expended 

 and the number of observations made. 



The first attempt to reduce this chaos to something like 

 order was made by Otto Friederich Miiller, of Copenhagen. 

 He thoroughly appreciated the work he was taking in hand. 



