November 8, 1895.] 



SCIENCE. 



607 



the French people of theu- beer makers, who 

 had been largely German, and when the 

 French people began to make their own 

 beer they found themselves for awhile in 

 difficulties. In spite of cai'eful methods 

 various imperfections in fermentations were 

 of frequent occurrence. By this time the 

 French public had become confident in 

 Pasteur's abilities, and it was only natural 

 that he should be requested to find the so- 

 lution for this puzzle. As usual, success 

 attended his efforts. His microscope soon 

 showed him that the ti'ouble was due to 

 the use of impure yeasts. The brewer's 

 yeast was liable to be mixed with various 

 species of bacteria as well as improper 

 species of yeasts, and his genius soon show- 

 ed methods of removing the difficulties and 

 bringing the fermentative industry into a 

 condition of uniformity. Upon the basis 

 of these experiments has been founded the 

 whole of our modern brewing industries. 

 The large brewery of to-day is impossible 

 without the microscope, and to the stimu- 

 lus given by these discoveries of Pasteur 

 has been due the great centralization of 

 brewing. 



The next problem that attracted the at- 

 tention of Pasteur was the dreaded an- 

 thrax. For several years this devastating 

 disease had been the subject of scientific 

 investigation. Already its connection with 

 micro-organisms had been made probable 

 and indeed had been demonstrated. Many 

 problems had been solved, but many still 

 remain to be solved in connection with this 

 pestilence of the agriculturist. As usual 

 Pasteur began at the beginning taking 

 nothing for granted, even of the facts that 

 had been essentially demonstrated. His 

 experiments resulted in a more complete 

 demonstration of the relation between the 

 anthrax bacillus and the disease, showed 

 the method of action of the germ, demon- 

 strated the source from which it was fre- 

 quently derived by cattle, differentiated 



between this disease and one or two others 

 closely resembhng it among animals, dis- 

 proved all of the objections that had been 

 raised by those who disbelieved in the causal 

 nature of the bacilli, and, in short, brought 

 this subject upon the same sure founda- 

 tion as that of pebrine which he had so 

 triumphantly solved ten years before. N"or 

 was this all. The greatest discovery oi 

 his life was to follow. To Pasteur's pecu- 

 liar trait of mind it was not enough to dis- 

 cover the cause without searching for the 

 remedy. It was the practical question 

 which appealed to him. Pasteur recog- 

 nized the fact that in the human race one 

 attack of an infectious disease frequently 

 renders an individual immune against a 

 second attack. He also remembered that 

 protection against small pox had been 

 known to be produced by vaccination. Act- 

 ing upon these suggestions the question 

 arose in his mind whether it were not pos- 

 sible to give to domestic animals, subject 

 to this devastating disease, a milder type 

 of the disease in question, from which they 

 should readily recover, but which would 

 give them immunity against a second at- 

 tack. The principle was a new one and 

 outlined a new, bold plunge into the mys- 

 teries of nature. It was not, however, in 

 the investigations of anthrax that the 

 remedy first suggested itself, but rather in 

 a side investigation upon the subject of 

 another germ disease known as fowl chol- 

 era. Every one is familiar with the results. 

 He discovered a method of rendering the 

 invading organisms of fowl cholera so im- 

 paired in their action as to be unable to 

 produce death, giving rise, on the contrary, 

 simply to a slight indisposition ; but dem- 

 onstration soon showed him that this slight 

 indisposition was followed by immunity 

 against the more severe disease. To an- 

 thrax he turned the same line of investiga- 

 tion, and after patient, laborious search dis- 

 covered a means of rendering the anthrax 



