“\ GRITICAL NOTICES OF NEW PUBLICATIONS. 335 
If the sanative effects of medicine could be ascertained by their pre- 
vious exhibition to brutes, and relied on for our guidance in pre- 
scribing for man, the immolation of a hecatomb of animals for 
health’s sake would be as justifiable as the slaughter of a herd of 
oxen for his esurience, and on the same grounds. Unluckily there 
are but few resemblances between man and most animals, in the 
operation of drugs on both. ‘The varying and sometimes opposite 
effects of medicines on horses are well known to veterinarians ; and 
disappointment on the subject might, we think, have been antici- 
pated, as nothing can well be more remote than the analogies on 
which rested the expectation of identical effects from the same sup- 
posed remedies. On horses, opium, mercury, nitrate of potass, sul- 
phate of magnesia, and antimony, are examples. Opium is vastly 
less striking in its effects as an anodyne and a narcotic: sulphate of 
magnesia (Epsom salts) is questionably aperient. Tartrite of anti- 
mony less striking as a diaphoretic (promoter of perspiration) ; and 
as an emetic it is not employed, from the fact of the horse’s stomach 
being anatomically inimical to such an operation. Nitrate of potass 
(nitre, or saltpetre) is inoperative, or very nearly so, as a diuretic. 
However, it is to observation more than to physiology we owe our 
knowledge of the value and effects of medicines: for their use is 
commonly empirical, though directed by the best informed. That 
carbonate of iron should in “ St. Vitus’s dance” (especially when oc- 
curring before puberty) be almost a specific ; that arsenic should 
have nearly the same effect on the same disease, when not depend- 
ing on diseased changes of structure of the brain ; that creosote, a 
newly-discovered essential oil, a product of the destructive distilla- 
tion of wood, sub-nitrate of bismuth, and hydrocyanic (prussic) acid, 
should be a// nearly omnipotent in obstinate vomiting not sympto- 
matic of inflammation of the stomach (gastritis) and a few other 
occasional causes, we owe to observation and experience ; and while 
we remain ignorant of their mode of action on the stomach and ner- 
vous system, we can hardly look to physiology for lights. 
But to physiology we owe infinite obligations for a knowledge, 
limited as it is, of the brain and nervous system ; and here this ele- 
vating science bids fair to be suggestive of something we may be 
able hereafter to accomplish for the treatment of their functional 
derangements. By proving the office and healthy operations of the 
respective divisions of those organs only can we ascertain, by their 
disturbance, the seat of the disease, which is ever formidable. In 
hydrophobia, epilepsy, tetanus, and insanity, we have nearly every 
thing to learn, if it is fated that any thing more is to be accom- 
plished. Already we can with certainty localise some affections, 
especially when the cause exists near the base of the brain. In like 
manner, internal injuries iuflicted by external violence have some- 
times their precise seat indicated by the symptoms; but these ad- 
vantages are among the benefits conferred by physiology, and their 
value is beyond calculation. The two most recent additions to this 
science are the works before us: different, yet alike. Dr. Elliot- 
