same description, which are nourished and grow as it seems by their own inherent vegetative principle, the true or natural parts of the body meantime shrinking and perishing. And this ap- parently because these tumours attract all the nourishment to themselves, and defraud the other parts of the body of their nu- tritious juices or proper genius. Whence the familiar names of phagedsena and lupus; and Hippocrates, by the words TO Oeiov, perhaps understood those diseases which arise from poison or contagion ; as if in these there was a certain vitality and divine principle inherent, by which they increase and through conta- gion generate similar diseases even in other bodies. Aristotle 1 therefore says : " all things are full of soul ;" and elsewhere he seems to think that " even the winds have a kind of life, and a birth and a death." 2 But there is no doubt that the vi- tellus, when it is once cast loose and freed from all connexion with the fowl, during its passage through the infundibulum and its stay in the cavity of the uterus, attracts a sluggish moisture to itself, which it absorbs, and by which it is nourished ; there too it surrounds itself with albumen, furnishes itself with mem- branes and a shell, and finally perfects itself. All of which things, rightly weighed, we must needs conclude that it is pos- sessed by a proper vital principle (anima).
EXERCISE THE TWENTY-EIGHTH.
The egg is not produced without the hen.
Leaving points that are doubtful, and disquisitions bearing upon the general question, we now approach more definite and obvious matters.
And first, it is manifest that a fruitful egg cannot be pro- duced without the concurrence of a cock and hen : without the hen no egg can be formed ; without the cock it cannot be- come fruitful. But this view is opposed to the opinion of those who derive the origin of animals from the slime of the ground. And truly when we see that the numerous parts concurring in
1 De Gen. Aiiim. lib. iii, cap. 2. 2 Ibid. lib. iv, cap. 10.
