46 
ON THE VETERINARY MATERIA MEDICA. 
to three drachms. Opium alone has often palpably failed ; but the 
catechu, with half a drachm of opium and an ounce of chalk, 
will often be of great service. It is an indispensable ingredient in 
the “ Calves’ Cordial,” or astringent medicine for the cure of the 
“ skit,” or u scouring,” or “ running out,” in sheep and calves; 
and still combined with opium and an absorbent, and more parti¬ 
cularly a carminative or aromatic being added. The dose would 
be, half a drachm to a lamb, one drachm to a sheep, and one 
and a half to a calf, with from ten grains to a scruple of opium, 
one to three drachms of prepared chalk, and one scruple of ginger 
or two of caraway powder. 
In the treatment of distemper-purging in the dog, it must never 
be omitted; for, owing to the irritable nature of the stomach of 
the dog, a sufficient quantity of opium can rarely be administered. 
The dose will vary from a scruple to a drachm, with from a quar¬ 
ter to half a grain of opium and the chalk, and ginger or cara¬ 
way. To vary the medicine in obstinate cases, powdered oak- 
bark may be given in the same doses. 
It is, perhaps, scarcely necessary to add, that in the use of cate¬ 
chu, and the astringents generally, except in superpurgation from 
physic, one or two doses of the neutral salts should be previously 
given, to carry off any acrid matter that may possibly cause or 
prolong the discharge: and that the practitioner will be exceed¬ 
ingly careful never to check those critical discharges by which 
Nature is freeing herself from that which offends, and on the 
encouragement of which a restoration to health may depend. 
A knowledge of chemistry, shamefully neglected in our national 
school, will show us, that few substances can be blended together 
without a change of properties being effected in them. That 
effect, for the sake of which a certain medicine is given, may, 
by the chemical action of another ingredient in the mixture, be 
weakened or destroyed, or dangerously increased, or even an 
effect perfectly contrary to that which was intended may be pro¬ 
duced. We should, therefore, give due attention to what Dr. Paris 
(whose u Pharmacologia” we would earnestly recommend to our 
young readers) calls the Incompatibles , or the substances which 
change or destroy the virtues of some of the ingredients. 
It must not be combined with any alkali, for the tannin w r ould 
unite with it, and form an inert compound—the tannate of that 
alkali; nor with any carbonate of an alkali, for the carbonic acid 
w 7 ould be driven off, and an inert tannate of the alkali w r ould re¬ 
main. We have, however, recommended the union of prepared 
chalk (carbonate of lime) with the catechu, and with the know¬ 
ledge that w 7 c w T ere losing much of the astringency of the catechu, 
and the neutralizing pow r er of the chalk. We unfortunately had 
