764 
PROFESSOR MORTON S 
pharmacy enables us to set free. The same may be said of many 
other principles. Chemistry has likewise much extended our do- 
main, and we now prepare other and, perhaps, more active agents 
from the mineral kingdom. I might refer you to the preparations 
of mercury, viz., calomel, and corrosive sublimate, which consist of 
the union of a metal with another elementary substance, chlorine. 
I might refer to the compounds of antimony, copper, iron, and 
zinc, and likewise to the concentrated and other acids, and to 
many other therapeutic agents, particularly to that very numerous 
class designated salts. It is to chemistry alone that we are in- 
debted for almost all of these, since nature never furnishes them, 
at least not in sufficient quantity as to be available for the use of 
man. 
By the aid of this science we likewise increase the potency of 
our remedies by a judicious combination of them ; and here, more 
than is generally thought by the uninstructed, will you require a 
knowledge of chemical laws; for if, on the one hand, their ac- 
tivity may be increased by union, so, on the other, it may be en- 
tirely destroyed. Two energetic bodies may form by union a 
third perfectly innocuous; or tw T o bland and inactive ones may 
give birth to another violent in action and even poisonous. As an 
instance of the first, we may take the union of the caustic alka- 
lies with the mineral acids; of the second, the combination of 
cynogen with hydrogen ; or of the metals with oxygen ; and 
many other elementary substances. 
1 feel assured that it is the neglect of the inculcation of the 
principles of chemistry which has led to the introduction of such 
gross compounds as are employed by many calling themselves 
veterinary surgeons. Most of these persons — for I am not speak- 
ing of the educated veterinarian — are fond of the employment of 
a multiplicity of drugs, jumbling them together without any 
consideration whether the operation of one may not be counter- 
acted by that of another; or whether chemical affinity does not 
come into play, and a new compound result from their union, 
the effect of which is the very reverse of that which they intended 
and desired to produce. 
Thus you will hear of their incautiously mixing sulphuric acid 
with the fixed and essential oils, so as to form a stimulating com- 
pound termed black oils; and serious consequences have followed 
their imprudence. The combination of alum and sulphate of 
copper with chalk, as an astringent — the union of the acetate of 
lead and sulphate of zinc as a collyrium, not knowing the mutual 
decomposition which here takes place — the addition of tincture of 
opium to the Goulard’s extract or diacetate of lead, for the same 
purpose, being perfectly unconscious of the fact, that the active 
