PASTEUR'S RESEARCHES IN GERM-LIFE. 91 



culture bad been carried on for some time at a loss. Tbe success bere 

 is described as marvelous ; tbe sale of cocoons giving to tbe villa a 

 net profit of twenty-six millions of francs.* From tbe imperial villa 

 M. Pasteur addressed to me a letter, a portion of which I bave already 

 publisbed. It may perbaps prove usefully suggestive to our Indian or 

 colonial autborities if I reproduce it bere : 



" Permettez-moi de terminer ces quelques lignes que je dois dieter, 

 vaincu que je suis par la maladie, en vous faisant observer que vous 

 rendriez service aux colonies de la Grande-Bretagne en repandant la 

 connaissance de ce livre, et des principes que j'etablis toucbant la mala- 

 die des vers a soie. Beaucoup de ces colonies pourraient cultiver le 

 mdrier avec succes, et, en jetant les yeux sur mon ouvrage, vous vous 

 convaincrez aisement qu'il est facile aujourd'bui, nonseulement d'eloi- 

 gner la maladie regnante, mais en outre de donner aux recoltes de la soie 

 une prosperite qu'elles n'ont jamais eue." 



Tbe studies on wine prepare us for tbe " Studies on Beer," wbicb 

 followed tbe investigation of silk-worm diseases. Tbe sourness, putrid- 

 ity, and otber maladies of beer Pasteur traced to special " ferments of 

 disease," of a totally different form, and tberef ore easily distinguisbed 

 from tbe true torula or yeast-plant. Many mysteries of our breweries 

 were cleared up by tbis inquiry. Witbout knowing tbe cause, tbe 

 brewer not unfrequently incurred heavy losses through the use of bad 

 yeast. Five minutes' examination with the microscope would have re- 

 vealed to bim the cause of the badness, and prevented him from using 

 tbe yeast. He would have seen the true torula overpowered by foreign 

 intruders. The microscope is, I believe, now everywhere in use. At 

 Burton-on-Trent its aid was very soon invoked. At the conclusion of 

 bis studies on beer M. Pasteur came to London, where I had the pleas- 

 ure of conversing with him. Crippled by paralysis, bowed down by 

 tbe sufferings of France, and anxious about bis family at a troubled 

 and an uncertain time, he appeared low in health and depressed in 

 spirits. His robust appearance when he visited London, on the occa- 

 sion of the Edinburgh Anniversary, was in marked and pleasing con- 

 trast with my memory of bis aspect at tbe time to which I have re- 

 ferred. 



While these researches were going on, the germ theory of infec- 

 tious disease was noised abroad. The researches of Pasteur were fre- 

 quently referred to as bearing upon the subject, though Pasteur him- 

 self kept clear for a long time of this special field of inquiry. He was 

 not a physician, and he did not feel called upon to trench upon the 

 physician's domain. And now I would beg of him to correct me if, 

 at this point of the introduction, I should be betrayed into any state- 

 ment that is not strictly correct. 



In 1876 the eminent microscopist, Professor Cohn, of Breslau, was 

 in London, and he then handed me a number of his "Beitr'age," con- 

 * The work on " Diseases of Silk-worms " was dedicated to the Empress of the French. 



