MEDICAMENTS AND LIFE. 215 
“complicated actions, and reduce them to simpler actions, 
more easily determined. ... Only experiments on animals 
enable us sufficiently to make those physiological analyses 
which will throw light and clearness upon the effects of 
medicinal substances as they are noted in man. In fact, 
we find that every thing we observe in man is repeated in 
animals, and vice versa, only with such peculiarities as the 
difference in their organisms accounts for; but the nature 
of physiological actions is fundamentally the same. It 
could not be otherwise, for, unless this were so, there 
could never be either any science of physiology or any sci- 
ence of medicine.”” The most famous of modern surgeons, 
Sédillot, has demonstrated, for his part, that surgical thera- 
peutics can have no other basis than the unchangeableness 
of vital phenomena in their relation of cause and effect. 
He has made it plain that the art must be founded on the 
unity and generality of science, instead of leaving it at the 
mercy of individual fancy. We now see in the clearest 
manner, thanks to the efforts of these two savants, how 
the study of those manifold resources which the physician 
has recourse to for the treatment of diseases may be advan- 
tageously pursued. 
1“ The unchangeableness of phenomena in their relation of cause and 
effect,” says Sédillot, “is a law without which no science, no observa- 
tion, no order, could be possible. Man, notwithstanding the very great 
complexity of the causes of his physiological manifestations, is no excep- 
tion to it. What has occurred once, in given circumstances, will be con- 
stantly represented under like circumstances, and a change in etiological 
conditions is the only reason for modifications in function. This fun- 
damental starting-point is indispensable for the physician, whose mind 
doubts and whose judgment is uncertain if he is not convinced of the 
constancy of facts submitted to his researches. No doubt the analysis 
he engages in is difficult; but, whatever its complexity, the most clear- 
sighted, attentive, and persevering observer will make discoveries in it 
every day, with the hope of still adding to their number, and of intro- 
ducing light and certainty where all was only darkness and confusion.” — 
Contributions to Surgery (Preface). 
