VETERINARY MATERIA MEDICA. 
4 ] 
with great discharge of offensive foecal matter, how is he always 
to determine between the use of a purgative, which the nature 
of the discharge seems to demand, or that of an opiate, which 
the irritation of the mucous coat of the intestines as imperiously 
requires? The difficulty will only be resolved by considering 
well the balance of indications, and obtaining a perfect know¬ 
ledge, not only of the evident action of the medicines employed, 
but of the shades of difference in the action of medicines that 
have apparently an effect of the same kind. 
The effects produced by medicines are controlled by many 
circumstances. The first and most important is the dose, both 
as it regards the action to be accomplished, and the extent of 
that action 5 and whether the effect is more likely to be produced, 
and will be more safely produced, by a succession of minute 
doses, or by the powerful energy of one large one. 
The quality of the medicines is an important and too neglected 
consideration, for the adulteration of the greater proportion of 
drugs frequently compromises the reputation of the practitioner * 
and the safety of the animal. 
The manner of preparing the different medicaments must not 
be overlooked. Few' of them can be used in their natural state. 
Care must be taken that they do not derive new and possibly 
dangerous qualities from the manner in which we are accus¬ 
tomed to prepare them. All drugs should be reduced to the 
finest state of powder; they will thus spread over a greater 
number of points at the same time, and produce a quicker and 
safer action. It is of advantage to give them, if possible, in a 
liquid form, for they are thus reduced to a state of greater 
tenuity, and, in the horse particularly, they more rapidly pass 
through the stomach and small intestines. M. Yvait proved 
that it scarcely occupies ten minutes for a fluid to pass from the 
mouth into the caecum of a horse. 
The circumstances of the case will influence the effect of the 
medicine, as the age, kind, sex, constitution, disease, and degree 
of strength of the patient, and the nature of the climate, and the 
season of the year. 
Medicines more readily act on young than on old animals. 
A colt of a year old will require one-third of that which is neces¬ 
sary for a full-grown horse. A two-year old will require one- 
half, and a three-year old, two thirds. 
The varieties of organization and sensibility in our different 
domestic animals have greater influence in determining the medi¬ 
cine and the dose. Herbivorous animals, from the structure and 
form of their stomach, rarelv vomit: while the vast extent of the 
intestinal canal in them, causes the medicine to be longer r«v 
vot. iv. G 
