Etiology : Causes of Disease. 



15 



diastase is inapplicable, as the diastase is produced by the living 

 cells of the germinal part of the seed, which are thus the coun- 

 terpart of the disease germ. No such glycogenic action occurs in 

 the seed that has been boiled or otherwise robbed of its vitality. 

 So with the arguments drawn from the ptyaline of the saliva, the 

 pepsin of the gastric juice, and the tr3^psin of the pancreatic 

 juice ; each of these is the product of the living cells of the gland 

 by which it is secreted, and cannot increase its own substance in 

 the absence of these cells. Like the enzyme of the bacteridian 

 ferment, these gland products can break down or digest certain 

 organic matters, but in all alike, the only source of the chemical 

 solvent is the living bacterium or gland cell from which the par- 

 ticular product is derived. The toxins of a virulent liquid, after 

 the sterilization of the latter may still produce most of tli2 lesions 

 and morbid phenomena of the disease, but, although death were 

 to ensue, the body of the victim would not be infecting to other 

 susceptible animals. The parallel between the funitions of the 

 secreting animal cells and the disease germs may thus be put in 

 tabular form : 



Living Source. Chemical Product, 



Salivary gland cells = Ptyaline 



Result. 

 = Starch changed to 



Sugar. 

 = Albuminoids chang- 

 ed to peptones in 

 acid solutions. 

 = Albuminoids chang- 

 ed to peptones in 

 alkaline solutions. 

 Toxin: Enzyme = Morbid phenomena. 

 Contagious disease. 

 Further consideration of pathogenic microorganisms will be 

 found in connection with contagious diseases. 



Peptic gland cells = Pepsin 



Pancreatic gland cells = Trypsin 



Disease germ 

 Disease germ 



