418 PHILOSOPHICAL TRANSACTIONS. [aNNO 1687.. 



a 28th of the whole weight of the living duck. In a rabbit, weighing lOoz. 

 7 dr. 50gr. we found 2 dr. 57gr. of blood ; which is about a 30th part. 



In the right ventricle and auricle of the heart of a dog, I found 6 oz. of 

 blood; after I had injected into the jugular vein a liquor that coagulated the 

 blood. I found a greater quantity of blood in the heart of another dog, which 

 I treated after the same manner. The hearts were much distended by the blood 

 found in them. I shall therefore suppose that 4oz. only were received at a time 

 by these hearts without force, that is, naturally ; and lest I should suppose 

 a greater quantity of blood to be admitted at a time than really is, I will suppose 

 a man's heart, which is much larger, and has much larger vessels, to receive 

 but 4oz. at each diastole. Allowing 75 pulses to every minute, there will be 

 4500 in an hour, and 1 8000 oz. of blood transmitted in that time. This last 

 number is the product of the foregoing 4500, being multiplied by 4, the number 

 of ounces at a diastole. 



Now if we suppose that a man's blood bears the same proportion to his 

 weight as that of any of the aforesaid animals had to its weight, which in a 

 lamb was the greatest, being ^V P^''t> it will follow that the quantity of circu- 

 lating blood in a man weighing l6olb. will not exceed 8lb. or 128oz. Ac- 

 cording to which computation the blood will circulate 140 times in an hour. 

 But let us suppose that instead of 8 lb. the mass of blood in such a man is 12 lb. 

 it will follow that it will circulate between Q3 and 94 times in an hour ; which is 

 a circulation and half, and somewhat more, every minute. I take this last com- 

 putation, to be very moderate, especially when it is considered that in the lamb 

 when opened there was scarcely a drachm of blood ; in the sheep not 3oz. to be 

 seen. From the celerity of the motion of blood now mentioned, we may give 

 a good account of the sudden refection with victuals, and particularly such as 

 are liquid ; we may also hence account for the quick passing of urine, and also 

 the quick motion of the chyle into the breasts of nurses, without supposing 

 unknown passages, from the stomach or any other part, into the bladder and 

 breasts. Half an ounce of blood at a diastole is the greatest quantity that I 

 remember any anatomist supposes to get into the heart, and they suppose the 

 quantity of blood in the body to be between 1 5 and 25 lb. by which it will appear 

 how their computations and mine differ. 



Account of Boohs. — /. Propositiones Hydrostatics ad illustrand. Aristarchi Samii 

 Systema destinatce, et qucedam Phcenomena Naturce Generalia. Auth. Fran- 

 cisco Jessop, Arm. Lond. Ato. 1687. N° IQl, p. 440. 



This book contains an hypothesis, and a pretended demonstration, concern- 

 ing the nature of bodies and their motions. The author defines a dense body 



