18 BACTERIOLOGY 



genius and an infinite capacity for taking pains, and fired too 

 by a love of his country and a desire to help humanity. His 

 researches into the nature of fermentation, and into the then 

 much vexed question of the spontaneous generation of life, 

 produced results of world-wide importance. He proved 

 conclusively that fermentation was due to organised and 

 living ferments, and that a special ferment (i.e. micro-organism 

 producing fermentation) corresponded with each variety of the 

 process. He at the same time proved by elaborate and care- 

 fully controlled experiments, to his own satisfaction and to 

 that of the vast majority of modern scientists, that " spontane- 

 ous generation of life " or abiogenesis, as it was called in 

 learned phrase, was a myth ; and that organic material, e.g. 

 fluid infusions of meat or the like, do not decompose, if they 

 are carefully guarded from the presence of contaminating 

 micro-organisms, a subject to which reference will again be 

 made in our Chapter on Sterilisation. Hurtful or noxious and 

 abnormal fermentation sometimes known as the " diseases " 

 of wines, vinegar, beer, etc., can similarly be prevented by certain 

 simple precautions, such as heating to a suitable temperature 

 and taking the precaution of allowing only the proper organism 

 to act in each case. In 1865, Pasteur also proved that the de- 

 vastating disease known as Pe*brine by which silkworms were 

 attacked, and which had nearly brought ruin upon one of 

 France's chief industries, was due to a protozoal parasite (Nosema 

 bombyces) ; and he was able, after studying its life-history, to 

 suggest a very simple but yet very efficacious procedure by 

 which its ravages might be prevented. 



The treatment of various diseases by u vaccines " next occu- 

 pied his attention. In 1877, widespread epidemics of Anthrax 

 had been carrying off enormous numbers of sheep and cattle in 

 France, whilst in Russia some 56,000 head of cattle were de- 

 stroyed in two years. Pasteur succeeded in artificially grow- 

 ing the bacillus which causes the disease, making use of a broth 

 medium for the purpose. He then proceeded to Chartres, 

 around which the epidemic had produced a loss said to have 

 amounted to little short of a million pounds, and studied the 

 disease on the spot. He found that if he inoculated cultures 

 of the bacillus grown artificially at blood temperature (98'6 F. 

 or 37 C.) into sheep, they all died ; but that, if he grew the 

 virus at a somewhat higher temperature, viz. 108 F. (or 42 C.) 

 at which the organism could still grow, but could not form 

 spores, and kept it for about a fortnight before using it for 

 inoculation, a mild or benign form of the disease was produced, 

 from which the sheep recovered, and were then found to be 

 immune to the ordinary fatal form of anthrax. 



