98 BACTERIAL POISONS. 



disease, before the proof that the given germ is the cause 

 of the disease be accepted as positive. 



Heretofore, the science of bacteriology has been largely 

 founded upon morphological studies. Bacteriologists have 

 given their time and attention to the discovery of bacterial 

 forms in the diseased organism and to observations of char- 

 acteristics in structure and growth of different species of 

 bacterial life. We must now study the physiology and 

 chemistry of the germs, and until this is done we must 

 remain ignorant of the true cause of disease, and so long 

 as we remain ignorant of the cause, it cannot l>e expected 

 that we shall discover scientific and successful methods of 

 treatment. Suppose that our knowledge of the yeast plant 

 was limited to its form and method of growth ; of how little 

 practical importance this knowledge would be. That the 

 yeast plant requires a saccharine soil before it can grow, 

 that given such a soil it produces carbonic acid gas and 

 alcohol, are the most important and practical facts which 

 have been ascertained in its study. Likewise, the condi- 

 tions under which pathogenic germs multiply and the pro- 

 ducts which they elaborate in their multiplification must 

 be ascertained before their true relationship to disease can 

 be understood. 



In saying that the morphological work upon which the 

 science of bacteriology rests almost wholly is inadequate, 

 we wish that it may be plainly understood that we are not 

 offering any hostile criticism upon the great men who have 

 done this work and who have formulated conclusions there- 

 from. The development of bacteriology has been in accord- 

 ance with the natural law governing the growth of all the 

 biological sciences. The study of form naturally and neces- 

 sarily precedes the study of function. The ornithologist 

 finds a new species of bird. He first studies its shape and 

 size, the color of its plumage, the form of its beak, the 

 number and arrangement of the feathers of the tail and 

 wing, the color of the eyes, etc. All this he can do with a 

 single specimen, recognizing the fact, however, that varia- 

 tions more or less marked are likely to be found in other 

 individuals. More time and wider opportunities of ob- 



