6

ELEMENTS OF MATE1UA MEDICA.

FiG. 6.

Festucn quadridentata (Kunth).

believe, with Dr. Christison (Treatise on Poisons, 3rd ed. p. 65,) that “ if thesubject be studied more deeply, the greater number of the alleged diversi-ties will prove rather apparent than real.”

The animals employed for the purpose of ascertaining the operation of ■medicines are, ordinarily, the dog and the rabbit, and, occasionally, the •’cat and the horse. The dog and cat are supposed to be “ affected by !almost all poisons exactly in the same way as ourselves,” ( Christison ,p. 64 ;) yet they offer some peculiarities deserving of notice, especially inthe case of narcotics. Their brains being much less developed than the 1cerebral organ in man, we naturally look for some diversity in the action ;of substances whose influence is principally directed to this viscus.Charvet, in describing the effects of opium [Be Faction comparee de FOpium, .