FERMENTATION. 135 



water, or, better still, in slightly alkaline solution, to bring 

 about direct hydration of the urea into ammonium car- 

 bonate. 



When it is asked what value the study of fermentation has been to the 

 cause of medicine, it is not necessary to go further for an example than 

 this urea fermentation. In the operations of the older surgeons it 

 was very frequently recorded that the introduction of instruments into the 

 bladder (in which, of course, was a solution of urea) was followed by a 

 regular fermentation, which too frequently led to the death of the patient ; 

 and it having been determined that micro-organisms were the cause of this 

 fermentation, it became an easy matter to prevent their introduction by 

 careful sterilization of the instruments ; and, as a result, such ammoniacal 

 fermentation within the bladder is now a matter of very infrequent occur- 

 rence, and is, in those cases in which it does occur, the result not so much 

 of accident as of carelessness on the part either of the patient or of the 

 surgeon. So marked, indeed, has this been, that even those who sneer at 

 bacteriology and antiseptics have been compelled to accept new methods 

 of procedure in regard to the cleanliness of their instruments, a cleansing 

 which means simply the removal of these minute vegetable protoplasmic 

 organisms, which, on being introduced into the suitable fermenting medium 

 in the bladder (or elsewhere), give rise to the alkaline fermentive, putre- 

 factive and other processes. 



In an interesting chapter on the butyric fermentation of 

 putrefaction, Schiitzenberger points out that in the process 

 of putrefaction or putrid fermentation, as it may be called, 

 there is a formation of butyric acid, one only of a series of 

 fatty acids formed under similar conditions ; accompanying 

 this there occurs a transformation of glucose, starch, lactic 

 acid, albuminoid substances, and the various fruit acids, into 

 these fatty acids, into carbon dioxide, and into certain 

 hydrogen compounds. From a very large number of these 

 substances lactic acid with or without carbon dioxide is 

 formed, whilst the lactic acid may be further split up into 

 butyric acid, carbon dioxide, and hydrogen. 



From this chapter we may borrow some of the formulae to 

 show how easy and how rational is the transformation from 

 these substances into the fatty acids. Other substances 

 may also be formed, these being further broken down or 

 separated as the case may be. Glucose, as we have already 

 seen, is, under the action of the lactic acid ferment, converted 

 into lactic acid, and this under the action of the butyric 

 ferment, a small rod-shaped organism from 1.8 to iS/* in 

 length and i.8j* in breadth is converted into butyric acid, 

 carbon dioxide, and hydrogen. These micro-organisms 



