CHAPTER XVII 



THE MOTION AND CIRCULATION OF THE BLOOD ARE 

 CONFIRMED FROM THE PARTICULARS APPARENT IN 

 THE STRUCTURE OF THE HEART, AND FROM THOSE 

 THINGS WHICH DISSECTION UNFOLDS 



I DO not find the heart as a distinct and separate part 

 in all animals ; some, indeed, such as the zoophytes, 

 have no heart ; this is because these animals are coldest, 

 of no great bulk, of soft texture or of a certain uniform 

 sameness or simplicity of structure ; among the number 

 I may instance grubs and earth-worms, and those that 

 are engendered of putrefaction and do not preserve 

 their species. These have no heart, as not requiring 

 any impeller of nourishment into the extreme parts ; 

 for they have bodies which are connate and homo- 

 geneous, and without limbs ; so that by the contraction 

 and relaxation of the whole body they assume and 

 expel, move and remove the aliment. Oysters, mussels, 

 sponges, and the whole genus of zoophytes or plant- 

 animals have no heart ; for the whole body is used as a 

 heart, or the whole animal is a heart. In a great number 

 of animals, almost the whole tribe of insects, we cannot 

 see distinctly by reason of the smallness of the body ; 

 still in bees, flies, hornets, and the like, we can perceive 

 something pulsating with the help of a magnifying glass ; 

 in pediculi, also, the same thing may be seen, and as 

 the body is transparent, the passage of the food through 

 the intestines, like a black spot or stain, may be 

 perceived by the aid of the same magnifying glass. 



In some of the bloodless 1 and colder animals, 



1 [i.e. Not having red blood.] 

 9 6 



