730 
INTRODUCTORY LECTURES. 
“ Thus animal medicine, like that of man, derives its funda- 
mental principles from the same sources — that vast collection of 
animals which covers the surface of the globe, or inhabits the re- 
gions of the air, or the depths of the sea. The organic elements 
are the same — the physiological laws are the same in all; and, in 
all, the machine is exposed to the same derangements. Man 
and the brute are alike condemned to live and to suffer, while 
analogous diseases, and often of precisely the same character, 
threaten and overwhelm them. What proof of this can be more 
striking than the benefits derived from vaccination — the most 
important medical fact that we possess ? Are they not the in- 
ferior animals which furnish man, I may almost say in return 
for the care which he bestows on them, with the only safeguard 
against this dreadful pest, which had thinned every previous 
generation ? 
“ The study of comparative disease is, then, as useful and as 
important as that of comparative anatomy. 
“ If the narrow limits to which I am now compelled to confine 
myself would permit, I might shew you the three kingdoms of 
natural history unfolding their treasures, in order to combat the 
diseases to which man and the brutes are jointly subject. I 
might speak of the successful labours of chemistry in unveiling 
all the affinities which play in the deep recesses of our various 
organs — the impenetrable laboratory of Nature. I might shew 
you every living being equally enveloped, acted upon, and modi- 
fied, without ceasing, by the agents which surround them, — the 
air, the light, caloric, and electricity. How shall we arrive at 
the knowledge of these common diseases if we are ignorant of 
all these agents, and their properties, and the divers modifica- 
tions which they impress on the economy of life ? and how diffi- 
cult and complicated must be that medical science which com- 
prehends such numerous and different elements? 
“ With reference to general economy, mechanics and physio- 
logy lend their aid to enable us to employ advantageously, and 
to multiply, the powers of our animals — those living! machines, 
those travelling manufactories — and to draw richer products from 
them. But I must confine myself to the consideration of our art 
in its reference to medicine. 
“ If veterinary medicine has borrowed from that of man — her 
elder sister — some general precepts which have guided her first 
steps, often, also, has she wandered with it in the labyrinth of 
theories and of systems. How could it be otherwise? The sci- 
ence of life, is it not as difficult in animals as in man ? And 
whatever part of this grand problem the votaries of either has 
studied, his progress is arrested at the first step. 
