879 
PHYSIOLOGY OF THE DOMESTICATED 
ANIMALS. 
The student of animal physiology — as the subject is set forth in, 
for example, such admirable manuals as those of Professor Huxley 
and Dr. Michael Foster — is continually sensible of a certain amount 
of difficulty in deciding to what extent any statement is generally 
applicable, or is more especially true of the human subject only. 
This difficulty is, in great part, obviated in Dr. Smith's well- 
printed volume 1 of nearly 1,000 pages. Dealing with a subject of 
high practical interest and importance, the author has, no doubt 
wisely, chosen to approach it solely through the scientific avenues. 
Accordingly, the first 160 pages are devoted to general physiology, 
and to that branch of it which is concerned with the physiology of 
animal cells. At the outset the structure of organised bodies claims 
attention, and this is followed by sections dealing respectively with 
the physics and the chemistry of the cell — this latter being regarded 
as the structural unit. The key to many abstruse problems, which, 
nevertheless, are constantly claiming the attention of the agricul- 
tural reader, will be found in this introductory portion. 
The second part of the work, dealing with special physiology, 
extends over 740 pages, few of which do not possess some direct 
interest for the breeder and feeder of live-stock. It embraces the 
following fifteen sections : — (1) Foods ; (2) digestion ; (3) absorption ; 
(4) the chyle ; (5) the lymph ; (6) the blood ; (7) the circidation of the 
blood ; (8) respiration ; (9) the mammary secretion ; (10) the renal 
secretion ; (11) the cutaneous functions ; (12) nutrition ; (13) animal 
heat ; (14 ) the physiology of movement ; (15) the physiology of the 
nervous system. 
The practically important subject of digestion is amply treated, 
the course of the food being traced through the mouth, oesophagus, 
stomach, small intestine and large intestine, and the sources and 
properties of the several digestive juices — the saliva, the gastric 
juice, the pancreatic juice, the bile, &c. — being detailed at con- 
siderable length. The chapter on the comparative digestibility of 
different food-stuffs is specially deserving of the attention of stock- 
feeders. It is false economy to pass through the alimentary canal 
of an animal any digestible food which, for some reason, escapes 
digestion. In many cases, especially in the food of cattle and sheep, 
the nutritive principles are contained in resisting envelopes which 
are impermeable to the digestive secretions, and which require 
mechanical reduction before they can be rendered accessible to the 
act of digestion. Imperfect mastication, therefore, to whatever cause 
it may be due, will diminish the digestibility of food. By this term, 
digestibility of food, is meant the amount of any food-stuff which, 
1 The Physioloqy of the Domestic Animals. By Robert Meade Smith, A.M. 
M.D. (F, A. Davis, Philadelphia and London, 1889.) 
