GREAT EPIDEMICS—ASIATIC CHOLERA. 301 
It not only suffers a marked change in its physical appear- 
ance, but it loses its original organic properties. It becomes 
impotent to perform the part of restorer which is imposed 
on it, Of what nature is this corruption of the albumen ? 
We cannot say, so long as we remain ignorant of the 
nature of that very albumen in its normal state. In other 
words, there will be no chance to begin the study of cor- 
ruptions of the blood until the blood of man in sound health 
shall be sufficiently understood, that is, until we shall have 
established the nature of the albuminoid substances with 
definite chemical exactness. That, for the moment, is the 
grand desideraium of biology. Chemistry is much ad- 
vanced, physiology is developing; that which remains 
stationary is the region of questions making the transition 
between those two sciences, and the answers to which, 
perhaps of little importance tc the former, would be the 
source of most desirable illumination for the latter. Nu- 
trition will never be explained until we shall have estab- 
lished exactly the formula for those transformations through 
which food passes from the moment it is dissolved in the 
stomach until the moment it is thrown off by the various 
emunctories under the form of products of disassimilation. 
Such an explanation would not only give the key to those 
difficulties in physiology which still hold savants in check, | 
but would also be of very great service in the knowledge 
of diseases, and, to return to our direct subject, in that of 
infectious diseases. It is therefore to the study of the albu- 
minoid substances, and of the complex, rapid, and infinite 
changes which they undergo in the blood, that capable ex- 
aminers should now direct their attention. Those who un- 
dertake it will not deserve the censure of setting out on a 
beaten path, for they will have every thing to create, be- 
ginning with the methods. At the present time we have 
never yet compared, and we have not even the means of 
comparing, in respect to the molecular elaboration that has 
