120 THE GERM THEORY OF DISEASE. 



over the products thus set apart by Sachs, we find that nearly 

 all of them may be set down at once as analogues of the urine 

 in the animals, of the alcohol, the acetic acid, the butyric acid, 

 etc., of the fermentations. 



It is to these products that we look for the most of the 

 vegetable substances now employed as medicines. The active 

 principles of these are the alkaloids. Therefore their effect 

 upon the animal economy is well known to medical students, 

 and need not be recited here. There are many other sub- 

 stances found in the same relationship to the vital energies of 

 the plant, which are worthy of special consideration, if we had 

 the time at our disposal. Tannic acid is one of the most constant 

 of these products, and there are a large number of others not 

 yet mentioned. We will only mention one other class of 

 substances, the coloring matters which remain in the wood 

 cells in a fixed condition, as a result of secondary metastasis. 

 Precisely similar phenomena are seen in the Micrococcus 

 Chromogenes, of which there are several varieties known. 

 All such circumstances serve to point us forward in our efforts 

 to explain the mysteries of nature. 



BACTERIA. 



When we come to consider the bacteria, and the allied 

 forms of life, we are at once amazed and astounded at the 

 wonderful power they possess in the remolecullzation of matter. 

 This is one of their especial characteristics. This seems to be 

 the form of life in which the largest amount of food material 

 is consumed, and the largest amount of waste products given 

 back, with the least building of tissue. The largest amount 

 of remoleculization with the least amount of formed or fixed 

 material. A whole jar of milk is turned sour, every particle 

 of its sugar of milk converted into lactic acid, and yet the 

 amount of the formed material is so insignificant that it re- 



