These observations are sufficient to show the importance of anatomy in certain surgical diseases. The state of medical opinion from the earliest ages to the present time, furnishes a most instructive proof of its necessity to the detection and cure of disease in general. The doctrines of the father of physic were in the highest degree vague and unmeaning. Every thing is resolved by Hippocrates into a general principle, which he terms nature; and to which he ascribes intelligence; which he clothes with the attribute of justice; and which he represents as possessing virtues and powers which he says are her servants, and by means of which she performs all her operations in the bodies of animals, distributes the blood, spirits, and heat, through all the parts of the body, and imparts to them life and sensation. He states that the manner in which she acts, is by attracting what is good or agreeable to each species, and retaining, preparing, and changing it: or, on the other hand, by rejecting whatever is superfluous or hurtful, after she has separated it from the good. This is the foundation of the doctrine of depuration, concoction, and crisis in fevers, so much insisted on by him and by other physicians after him; but when he explains what he means by nature, he resolves it into heat, which he says appears to have something immortal in it. The great opponent of Hippocrates was Asclepiades. He asserted that matter, considered in itself, is of an unchangeable nature: that all perceptible bodies are composed of a number of small ones, termed corpuscles, between which there are interspersed an infinity of small spaces totally void of matter: that the soul itself is composed of these corpuscles: that what is called nature is nothing more than matter and motion: that Hippocrates knew not what he said when he spoke of nature as an intelligent being, and ascribed to her various qualities and virtues: that the corpuscles, of which all bodies are composed, are of different figures, and consist of different assemblages: that all bodies contain numerous pores, or interstices, which are of different sizes: that the human body, like all other bodies, possesses pores peculiar to itself: that these pores are larger or smaller, according as the corpuscles which pass through them differ in magnitude: that the blood consists of the largest and the spirits and the heat of the smallest. On these principles Asclepiades founded his theory of medicine. He maintains that, as long as the corpuscles are freely received by the pores, the body remains in its natural state: that, on the contrary, as soon as any obstacle obstructs their passage, it begins to recede from that state: that, therefore, health depends on the just proportion between these pores and corpuscles: that, on the contrary, disease proceeds from a disproportion between them: that the most usual obstacle arises from a retention of some of the corpuscles in their ordinary