432 
Some Relations of Biolof/y to Agriculture. 
pathology iu its relations to general biolog)'. He defined biology 
as the study of life in all its forms and activities, both normal and 
abnormal. No branch of knowledge can exceed this in interest and 
importance ; none has made greater advances during this century of 
scientific progress. Pathology is that section of biol ogy which deals with 
the study of life in its abnormal forms and activities. It embraces 
the investigation of the causes of disease, of the anatomical changes 
produced by disease in the organs and tissues of the body, and of 
the alterations in function resulting from disease ; it therefore 
constitutes the scientific basis of practical medicine. Preventive 
and curative medicine is constantly making beneficent applica- 
tions of pathological discoveries, and the most intelligent and effi- 
cient treatment of disease is becoming more and more that which 
is founded upon the most accurate knowledge of its nature and 
causes. 
As an illustration of the achievements of modern pathology, it is 
instructive to contrast the imperfect, meagre, and confusing infor- 
mation of former times with the extent of our present knowledge con- 
cerning one of the greatest of disease-scourges — tuberculosis. Merely 
a few years ago, not only was the specific cause of tuberculosis un- 
known, but there was no general appi'eciation of the fundamental 
fact that this is one of the infectious diseases. The knowledge of the 
frequency, and wide distribution, of tuberculous disease in other parts 
of the animal body than in the lungs is an acquisition of modern 
pathology. The pathological anatomy of tuberculosis, which not long 
ago was one of the most confusing chapters in pathology, has been 
made clear. The greatest addition to our knowledge of tuberculosis, 
and, in fact, one of the greatest achievements of modern science, is 
the discovery of the specific living germ which causes the disease in 
question. It is now practicable to study, both within and without the 
body, the form and properties of tliis germ, as well as the conditions 
which are favourable and those which are hostile to its preservation 
and development. 
The points of contact between animal and vegetable pathology 
are more numerous than might at first glance appear. The student 
of animal pathology can draw many instructive lessons from such 
subjects as the behaviour of wounds and parasitic affections in plants. 
Too much, perhaps, is made of the separation between the pathol9gy 
of man and that of the lower animals. While there is a wide dis- 
tinction in the dignity of the object of study, yet, from a scientific 
point of view, this separation is of little account. Pathological 
investigations of the diseases of animals constitute no less genuine 
and valuable contributions to pathology in general than do similar 
investigations of human diseases. The advancement in recent years 
in the education and aims of those who devote themselves to the 
study of animal patiiology will serve to bring into closer relationship 
the students of human and those of comparative medicine. Insist- 
ance is laid on the fact that the pathologist, whose sole knowledge of 
quch a disease as tuberculosis is derived from the study of the dis- 
order as it occurs in man, has a far less complete understan ding of it 
