BOTANY AS APPLIED TO VETERINARY SCIENCE. 669 
talacum is an annual plant, attaining a height of from four 
to six feet, with large green leaves, some of which are nearly 
two feet long and four inches broad ; flowers in July and 
August, having pale-pink flowers, and is the variety chiefly 
cultivated in America. The general physical properties of 
the leaves, when cutup into ordinary tobacco or ground into 
snuffj are more or less familiar to all, although its dangerous 
properties by its use as a luxury may not be so generally under¬ 
stood. The following is a view taken of its effects by an 
eminent writer:—Beneficial as in some cases tobacco may 
prove in its character as a medicine, its use as a luxury in 
any form is as injurious as its intoxicating properties are 
lamentably demoralising. At its commencement it causes, 
like opium, intoxication and sickness; but by continued 
use in moderation these unpleasant symptoms subside into 
a sort of fascinating, dreamy state of semi-intoxication, 
which insidiously attacks the health, making disease and dis¬ 
organization creep by silent and stealthy steps into the 
system, and drink up the spring of life, until its fountain is 
drained/^ 
Its active properties depend upon a peculiar volatile alka¬ 
loid, named nicotina, which possesses the following cha¬ 
racters :—It is an oily, volatile liquid, of a pale-amber colour, 
having an odour of tobacco, with an acrid, burning taste, 
which remains upon the tongue for some considerable time. 
Its sp. gr. is ]'048, it is alkaloid, and forms salts with acids, 
mixes readily with water, and is soluble in alcohol, ether, and 
the fixed oils. It constitutes from four to twelve in 1000 of 
tobacco, and is a very powerful poison, resembling prussic 
acid. It also resembles prussic acid in the fact that it is a 
compound of carbon, nitrogen, and hydrogen, and it con¬ 
tains no oxygen As a medicinal agent, it acts 
as a sedative and antispasmodic, also emetic, laxative, and 
diuretic, but is rarely administered to animals except in the 
form of clyster; in the gaseous form, as smoke, it has proved 
highly beneficial in cases of severe colic, constipation of the 
bowels, and hernia. As an outward application, it is used 
to destroy the acari, in scab in sheep and mange in horses, 
also to destroy flees, lice, and other parasites, but should be 
applied with care, as serious consequences have followed its 
absorption. 
As a poison, its effects upon the human subject have in 
many instances proved fatal. Hertwig found that the 
pulse was lowered in number, and rendered intermittent and 
irregular, by doses given to horses varying from half an 
ounce to an ounce of the powdered leaves. An ox, after 
