FERMENTATIVE GERMS. 15 



triplication of living germs accompany the process, aud these 

 germs are called a "ferment." 



In the secretions of the salivary glands there is a ferment 

 which dissolves albuminoids and changes sugar into an acid, 

 and these effects may be carried on after the secretions have 

 been separated from the body of the animal, and can be con- 

 tinued from parcel to parcel of matter, as in any other case 

 of fermentation. In my investigations of rennet, I found the 

 active agent to consist of minute germs, which proved to be 

 the spores of blue mould. I watched them through their 

 changes till they threw out filaments of mould, and multiplied 

 by seed-balls on. the ends of those filaments. The action in 

 rennet is that of a ferment or true yeast, and may be contin- 

 ued indefinitely from one batch to another. The ohanges 

 which occur in the kidneys and bladder appear to be of the 

 same nature. I have found germs in the bladder analogous 

 to those in the stomach, and used them to carry on a continued 

 series of changes after they had been separated from that 

 organ. And lately the action of the pancreas in converting 

 chyme into chyle has been proved to be the action of a 

 ferment or yeast. The germs are now separated from the 

 secretions of those glands, and used as a remedial agent, the 

 secretions, after the removal of the germs, being entirely 

 inert. From their close resemblance to the rennet germs, 

 they are supposed to have a similar origin. 



Finding so many of the secretions of the body exerting 

 their modifying influences through the agency of organic 

 germs, it might reasonably be expected that the secretions of 

 the mammary glands would not be free from them. Accord- 

 ingly, we find milk to contain ferments which work changes 

 in it both before and after it leaves the udder. The action 

 of the mammary glands imitates that of the stomach in 

 another respect. The double function of the stomach in 

 throwing into its cavity a secretion abounding with a 

 digestive yeast, and, at the same time, absorbing the con- 

 tents of the stomach made liquid by that yeast, is imitated in 

 a measure by the lacteal glands. The tubes which permeate 

 those glands are lined with absorbent vessels, which are con- 

 stantly taking up the milk that flows through them, and their 

 activity is so great that a moderate secretion of milk will be 



