762 The. American Naturalist. [September, 
No more striking illustration of the practical benefits con- 
ferred by biological discoveries can be given than that derived 
from the investigation of those lowly micro-organisms which 
are partly our friends, the preservers of the very existence of 
life upon this globe, and in smaller part our enemies, the 
causes of infectious diseases. It would be a long story should I 
attempt to rehearse the useful discoveries in this domain; how 
Pasteur saved the silkworm industries of France by his studies 
of a microscopic parasite; how agriculture and dairies and 
industries concerned with fermentative processes have been 
benefited ; how preventive inoculations have saved the lives 
of thousands of animals; how surgery has been revolutionized 
by Lister’s application of Pasteur’s discoveries; how the scien- 
tific study of immunity has opened up new vistas in prevent- 
ive and curative medicine, as exemplified by the antitoxic 
treatment of diphtheria and preventive inoculations for rabies, 
which have led to the saving of untold thousands of human 
lives. All of the money ever expended for the promotion of 
biological science has been repaid a thousand fold by the use- 
ful applications of biological discoveries, and in making this 
statement in this presence I trust that I shall not be thought 
for a moment to countenance that Philistine view of science 
which would estimate its value in money or in immediate 
practical utility. 
I have already had occasion to touch upon another side of 
biology, which is not at present here provided for and which 
may not be so familiar to all as a biological science. I refer 
to pathology or the study of life in its abnormal forms and 
activities. This is the pure science of medicine as distinguished 
from the art of healing. It is just as truly a department of 
biology as is the study of normal life. The relations of patho- 
logy to practical medicine are so intimate that the broader 
conception of this science as a part of biology is not always 
appreciated. Nevertheless pathology may be cultivated as a 
science no more subordinated to practical ends than is any 
other natural science. Its subject matter is any living thing 
which deviates from the normal condition. Its province isto 
investigate abnormal structure, disordered function and the : 
