74 MOTION OF THE 



the chick many days after its exclusion, and is a substitute for 

 the milk to other animals. 



But these matters will be better spoken of in my observations 

 on the formation of the foetus, where many propositions, the 

 following among the number, will be discussed : Wherefore is 

 this part formed or perfected first, that last ? and of the several 

 members : what part is the cause of another? And many points 

 having special reference to the heart, such as : Wherefore does 

 it first acquire consistency, and appear to possess life, motion, 

 sense, before any other part of the body is perfected, as Aristotle 

 says in his third book, De partibus Animalium? And so also 

 of the blood : Wherefore does it precede all the rest ? And in 

 what way does it possess the vital and animal principle ? And 

 show a tendency to motion, and to be impelled hither and 

 thither, the end for which the heart appears to be made? In 

 the same way, in considering the pulse : Wherefore one kind of 

 pulse should indicate death, another recovery? And so of all the 

 other kinds of pulse, what may be the cause and indication of 

 each. So also in the consideration of crises and natural critical 

 discharges ; of nutrition, and especially the distribution of the 

 nutriment; and of defluxions of every description. Finally, re- 

 flecting on every part of medicine, physiology, pathology, se- 

 meiotics, therapeutics, when I see how many questions can be 

 answered, how many doubts resolved, how much obscurity illus- 

 trated, by the truth we have declared, the light we have made 

 to shine, I see a field of such vast extent in which I might 

 proceed so far, and expatiate so widely, that this my tractate 

 would not only swell out into a volume, which was beyond 

 my purpose, but my whole life, perchance, would not suffice for 

 its completion. 



In this place, therefore, and that indeed in a single chapter, 

 I shall only endeavour to refer the various particulars that pre- 

 sent themselves in the dissection of the heart and arteries to 

 their several uses and causes; for so I shall meet with many 

 things which receive light from the truth I have been contend- 

 ing for, and which, in their turn, render it more obvious. And 

 indeed I would have it confirmed and illustrated by anatomical 

 arguments above all others. 



There is but a single point which indeed would be more cor- 

 rectly placed among our observations on the use of the spleen, 



