1875.] Notices of Books. 363 
An Experimental Inquiry into the Nutrition of Animal Tissues. 
By Wixu1am Marcert, M.D., F.R.S. London: Longmans 
and Co. 
Tue nature of this interesting memoir may best be shown by a 
brief sketch of the conclusions at which the author has arrived. 
He holds that there is a safe ground for believing that the 
elementary constitution of muscle and other animal tissues 
is similar to that of a jelly, with this distin¢tion—that its 
fibrinous or cellular form gives it due tenacity for the performance 
of its functions, but its water, albumen, and other constituents, 
hold the same physical relation as would water to gelatine in 
jelly. All tissues are formed of three different classes of sub- 
stances,—those which constitute the ripe tissue, or the portion 
insoluble in water; those constituting the nutritive material of 
the tissues which are soluble in water, and colloid; and, lastly, 
the effete material which is also soluble but crystalloid, and con- 
sequently diffusible. In chemical composition the nutritive 
material and mature tissue do not differ, the change being simply 
morphological, and consisting in the assumption of an organised 
form. The whole of the phosphoric acid in muscular tissue is 
eliminated either as neutral tribasic phosphate or as pyro- 
phosphate of potash. In flesh there exist, however, certain 
amounts both of phosphoric acid and of potash, which are not 
in the proportions of any known phosphate, and which take part 
exclusively in the actual formation of the mature tissue. The 
albuminous constituents of muscular tissue appear to be elimi- 
nated in the process of waste, in the state of kreatin, kreatinin, 
and other crystalloid bodies. Blood yields to flesh considerably 
more potash than is actually required in the formation of mus- 
cular tissue, the excess serving to eliminate the phosphoric acid 
by converting it into a crystalloid salt. In the lungs, however, 
Mr. Marcet thinks there is good reason to believe that the potash 
is eliminated, not exclusively as phosphate, but to a great extent 
as a crystalloid carbonate, in consequence of the carbonic acid 
emitted from the blood whilst passing through the lungs. The 
effete material in the muscles contains phosphoric acid and pot- 
ash, in the respective proportions of 43 and 57; that in the lungs 
in the proportion of 11°32 to 88°68. 
He finds that wheat flour, potato, and rice contain certain 
amounts of colloid phosphoric acid and colloid potash, which in 
these three kinds of vegetables exist nearly in the proportions of 
I part of total phosphoric acid to 0°55 of colloid phosphoric acid, 
and 1 part of total potash to 0-24 of colloid potash. This state- 
ment is based on the following experiment :—‘‘ 100 grammes of 
wheat flour were mixed with enough distilled water for the whole 
to be nearly liquid: this was placed in a dialyser, which was 
floated for 24 hours over a bulk of water equal to 8 or 10 times 
that of the contents of the dialyser; the volumes of the contents 
of the dialyser and of the solution outside were then determined. 
