MOTION OF THE HEART AND BLOOD 



what is called a tail, and I have shown it living to 

 others. 



In these bloodless animals the heart beats slowly, 

 contracting sluggishly as in moribund higher animals. 

 This is easily seen in the snail, where the heart lies 

 at the bottom of that opening on the right side 

 which seems to open and close as saliva is expelled. 

 The incision should be made on the top of the body 

 near the part corresponding to the liver. 



It is to be noted that in winter and cold seasons, 

 the bloodless animals, as the snail, show no pulsa- 

 tion. They seem to live like vegetables or those 

 things called plant-animals. 



It is also to be noted that an auricle or its analogue 

 is present in all animals possessing a heart, and 

 where there is a double ventricle, there are always 

 two auricles, but not the reverse. But turning 

 to the development of the chick in the egg, there 

 is, as I said, only a vesicle or auricle, at first, or a 

 throbbing drop of blood, which, as growth pro- 

 gresses, becomes the heart. So in some animals, 

 not reaching the highest organization, as bees, 

 wasps, snails, shrimps, and craw-fish, there is a 

 throbbing vesicle or an alternately red and white 

 point, as the mainstay of life. 



There is a small squid, called a shrimp in English, 

 een gerneel in Flemish, which is caught at sea and 

 in the Thames, whose entire body is transparent. 

 Placing this creature in water, I have often shown 

 some of my friends the movements of its heart with 



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