[ 217 J 



XLIIT. On muscular Motion. By Anthony Carlislk, 

 Esq. F. R. S. : being the Croonian Lecture. Read before 

 the Royal Society November 8, 1804. 



[Concluded from p. 123.] 



JL HE following animals were put into separate srlass vcs* 

 sels, each filled with a pound weight of distilled water, pre- 

 viousjy boiled to expel the air, and the vessels inverted into 

 quicksilver; viz. one gold fish, one frog, two leeches, and 

 one fresh water muscle*. These animals were confined 

 for several days, and exposed in the sun in the day-time, 

 during the month of January, the temperature being from 

 43° to 4S° ; but no air bubbles were produced in the ves- 

 sels, nor any sensible diminution of the w-ater. The frotr 

 died on the third day, the fish on the fifth, the leeches on 

 the eighth, and the fresh water muscle on the thirteenth. 

 This unsuccessful experiment w-as made with the hope of 

 ascertaining the changes produced in water by the respira- 

 tion of aquatic animals, but the water had not undergone 

 any chemical alteration. 



Animals of the class mammalia, which hybernate, and 

 become torpid in the winter, have at all times a power of 

 subsisting under a confined respiration, which would de- 

 stroy other animals not having fhis peculiar habit. In all 

 the hybernating mammalia there is a peculiar siructure of 

 the heart, and its principal veins: the superior cava divides 

 into two trunks ; the left, passing over the left auricle of 

 the heart, opens into the inferior part of the right auricle, 

 near to the entrance of the vena cava inferior. ^ The veins 

 usually called azygos accumulate into two trunks, which 

 open each into the branch of the vena cava superior, on its 

 own side of the thorax. The intercostal arteries and veins 

 in these animals are unusually large. 



This tribe of quadrupeds have the habit of rolling up their 

 bodies into the form of a ball during ordinary sleep, and 

 they invariably assume the same attitude v/hen in the torpid 

 state : the limbs are all folded into the hollow made by the 

 bending of the body; the clavicles, or first ribs, and the 

 sternum, are pressed against the fore part of the neck, so 

 as to interrupt the flow of blood which supplies the head, 

 iand to compress the trachea: the abdominal viscera and 

 the hinder limbs are pushed against the diaphragm, so as 

 to interrupt its motions, and to impede the flow of blood 

 through the large vessels which penetrate it, and the lon» 



• Mijt'ilus tnatinuf. 



gitudinal 



