346 
EFFECTS OF MEDICINE ON HOUSES. 
appearance, without any trace of arsenic whatever, the entire 
poison having passed off in the urine during the six days imme- 
diately following the introduction of it into the system. The 
harmlessness of the poison on the dog, as compared with the 
sheep, may be accounted for from the far smaller extent (about 
one-fifth) of the intestinal canal, as well as the much greater 
muscularity of the tissues connected with the digestive organs 
of the carnivorous animals : these causes render the digestion, 
absorption, and the secretions, generally much more active in 
the dog than the sheep. 
THE EFFECTS OF MEDICINE ON HORSES. 
By Mr. W. Percivall. 
ARSENIC. 
The common white arsenic of the shops — the Acidum 
Arsen iosuxm of the London Pharmacopoeia — is a mineral 
so universally poisonous that vegetables, as well as animals, 
suffer and die from its influence. Seeds soaked in a solu- 
tion of arsenic are deprived of the power of germination ; buds 
immersed in it lose their capability of development ; plants 
watered or rubbed with it, die ; and to animals, without I be- 
lieve an exception, arsenic proves a deadly poison. 
Notwithstanding its universality and virulence as a poison, 
arsenic has long been introduced into medicine as a remedy for 
certain diseases, and has been, and continues to be, extensively 
used, both externally and internally. In minutely divided doses, 
such as the twentieth of a grain, continued for a considerable 
time, it is said by some to have a tonic effect upon man ; to 
augment his appetite, improve his digestion, and increase his 
strength. In larger does — from the twelfth to the sixteenth of a 
grain — arsenic has proved a valuable remedy in certain diseases 
of a periodic nature, and particularly in intermittent fevers, in 
which it has been known to succeed even where cinchona and 
quina have both failed. Over diseases of the skin arsenic has also 
manifested considerable power, both as an internal and an external 
remedy. Indeed, Sir Benjamin Brodie has shewn, by experi- 
ments on dogs and rabbits, that where arsenic has been employed 
externally, applied to wounds for example, the inflammation 
