166 
REVIEW OF MOIROUD’s 
by the removal of the most frequent source of constitutional irri¬ 
tation, an accumulation of faecal matter, or whether it is to be 
traced to the augmented secretion from the intestinal vessels. 
Another important effect follows, which is a revulsion of the 
blood, which is determined with less power to the head and ex¬ 
tremities, and more confined to the centre of the frame. It is 
on account of these effects that purgatives may sometimes be 
considered as tonics, sometimes as having a debilitating effect, 
and in other cases acting as revulsives. 
It is evident from this that they are useful in a great variety of 
maladies, as dropsy of the abdomen or cellular tissue, chronic 
affections of the skin or eyes, vertigo, worms, colic, and some 
catarrhal complaints. They are also exceedingly beneficial in 
acute inflammations, by getting rid of irritation from one part of the 
frame; but in these cases the mildest purgatives must be admi¬ 
nistered, for the drastic ones would be dangerous, on account of 
their irritating properties. Acute inflammations of the intestinal 
canal imperiously counter-indicate the use of drastic purgatives. 
When the purgative effect is too violent, or too much pro¬ 
longed, whether because such medicines were really counter- 
indicated, or given in too great a dose, superpurgation is said to 
be induced. The fsecal matter is then often evacuated with pain, 
and mingled with streaks of blood. In this case we must have 
recourse to emollients, opiates, and sometimes to the most pow¬ 
erful sedatives. 
There are few medicines the administration of which require 
so much precaution as purgatives. The patient should be pre¬ 
pared by peculiar food (mashes), and sometimes by emollient 
clysters ; he should be kept moderately warm, in a dry situation, 
and gentle exercise should be used. The dose, and the mode of 
administration, should be regulated by the climate, the season, 
and the age and constitution of the animal. 
To the ruminant they should be given in a liquid or pultaceous 
form, that may pass directly into the true stomach. If they 
penetrate into the rumen, they will remain there without pro¬ 
ducing their intended effect, on account of the enormous mass 
of food with which they will be mingled, and the little sensibility 
of the membrane of that reservoir. 
In spite of all our precautions, however, nothing is so uncer¬ 
tain as the effect of a purgative; for the most drastic and irritating 
will sometimes produce very slight evacuation, although they 
will sadly exhaust the patient, while some laxatives will provoke 
repeated and copious dejections without exhaustion. 
Although some of these medicines are termed laxative , their 
mode of action bears no resemblance to that of emollients. Their 
