REVIEW. 
173 
race, sex, and temperament ; nor should mode of life be over- 
looked by the veterinary practitioner. The consequences 
attendant on a long-continued use of certain substances Rre 
next dwelt upon, followed by the different action produced 
by the same agent in health and disease. To this succeed 
the ways in which medicines enter the system, and the 
manner in which purgatives operate, with their divisions. 
“ Cathartics may be defined as medicines which quicken or increase alvine 
evacuations ; they produce their effect in various ways. Some act by merely 
exciting the muscular fibres of the intestines to increased peristaltic motion, 
and thus cause their contents to be more quickly and more completely 
evacuated; some stimulate the mucous follicles and exhalents, so that a 
larger quantity of fluid than usual is excreted from the inner coat of the in- 
testines, and thus the fsecal evacuations are rendered more liquid and more 
copious. In many, both of these properties are united, and some extend 
their stimulus to the neighbouring viscera also, and hence produce an 
increased discharge of the supplementary intestinal secretions, as the bile 
and pancreatic juice.' Cathartics differ also as to the part of the intestinal 
canal on which they act ; the effect of some being confined to the small, aud 
others to the large intestines, while many of them appear to stimulate the 
entire tube ; they differ, moreover, as to the degree in which they produce 
their effects, and hence have been divided into three classes : 
“ 1. Laxatives , which operate so mildly as merely to produce the evacua- 
tion of the intestinal contents, without producing increased secretion or 
stimulating any of the neighbouring viscera. 
“ 2. Purgatives, commonly so called, which besides remarkably increasing 
the peristaltic action of the intestines, occasion increased excretion of the 
fluids from the exhalent vessels from the neighbouring viscera. 
“ 3. Drastic cathartics, which operate in the same manner as purgatives, 
but with much greater energy. 
‘Tn order to understand the manner in which cathartics act, it is neces- 
sary to have a knowledge of the formation, arrangement, and functions of 
the alimentary canal (which includes the stomach and the small and large 
intestines), and of the neighbouring viscera, which are implicated in the 
function of digestion, namely, the liver and pancreas.” 
Our author now enters upon the anatomy and physiology 
of the various organs implicated ; after which, the natural 
and chemical history of the various agents resorted to by the 
practitioner of veterinary medicine is given, namely, aloes in 
its several kinds, oils of linseed, olive, castor, and croton, 
calomel, sulphur, and the sulphates of magnesia and soda, 
with the adjuvants — clysters and mashes. 
Now, although there may not be much that is absolutely 
new in this, yet there is a freshness in the description, and 
an agreeable interspersing with facts, an acquaintance with 
