He appears to have come nearer the truth where he says : J " The other basis of the parts to be formed first or last is obtained from nature, that is, from the vital principle by which the animal body is ruled and directed. If there be two grades of this prin- ciple, the vegetative and animal, the vegetative must be held prior in point of nature and time, inasmuch as it is common to plants and animals ; and assuredly the organs officiating in the vegeta- tive office will be engendered and formed before those that belong to the sensitive and motive principle, especially to the chief organs which are in immediate relationship with the governing prin- ciple. Now these organs are two in especial the liver and the heart : the liver as seat of concupiscence, of the vegetative or nu- tritive faculty; the heart, as the organ whose heat maintains and perfects the vegetative and every other faculty, and in this way has most intimate connexions and relations with the vegetative force. Whence, if after the third day you see the heart palpi- tating in the point where the chick is engendered, as Aristotle bears witness to the fact that you can, you will not be surprised but rather be disposed to admit that the heart belongs to the vegetative degree and exists for its sake. It is also consonant with reason that the liver should be engendered simultaneously with the heart, but should lie perdue or hidden, as it does not pulsate. And Aristotle himself admits that the heart and liver exist in the animal body for similar reasons; so that where there is a heart there also is a liver discovered. If the heart and liver be the parts first produced, then, it is also fair to suppose that the other organs subserving these two should be engen- dered in the same manner, the lungs which exist for the sake of the heart ; and, for the sake of the liver, almost all the vis- cera which present themselves in the abdomen."
Still is all this very different from the sequence we witness in the egg. Nor is it true that the liver is engendered simulta- neously with the heart ; nor does the salve avail with which he would cover that infirmity where he says that the liver is con- cealed because it does not palpitate ; for the eyes and vena cava and carina are all conspicuous enough from the com- mencement, although none of them palpitate. How come the liver and lungs, if they be then extant, to be visible without any palpitation ? And then Fabricius himself has indicated a 1 Op. cit. ut. sup.
