THE BLOOD. 3 



They likewise say, that the heat should be less than that of 

 the animal, or than 98 of Fahrenheit's thermometer; and 

 that, if fresh blood be received into a cup, and that cup put 

 into water heated to 98, it will not separate ; nay, they even 

 say, that it will not coagulate ; but this, I am persuaded from 

 experiments, is ill founded (n). 



EXPERIMENT I. 



A tin vessel, containing water, was placed upon a lamp, 

 which kept the water in a heat that varied between 100 

 and 105. In this water was placed a phial, containing 

 blood that instant taken from the arm of a person in health ; 

 the phial was previously warmed, then filled, and corked to 

 exclude air. In the same water was placed a teacup half full 

 of blood, just taken from the same person ; a third portion of 

 the blood was then received from the same vein into a basin, 

 and was set upon a table, the heat of the atmosphere being at 

 67. Now, according to their opinion, the two former should 

 neither have coagulated nor separated, when that in the basin 

 began to separate ; but, on the contrary, they were all three 

 found to coagulate nearly in the same time ; and those in the 

 warm water not only did separate as well as the other, but 

 even sooner. 



EXPERIMENT II. 



The same experiment was repeated on the blood of a person 

 that laboured under the acute rheumatism, whilst the heat of 

 the atmosphere was no higher than 55, and that of the warm 

 water was 108 ; and the result of this experiment was not 

 only a confirmation of what was observed in the first, but it 

 even showed, that this degree of heat was so far from lessen- 



(TI.) Dr. Butt a says, that blood taken from a vein remains fluid if 

 kept at the heat of the living body, and that at about 32 the blood con- 

 cretes into an uniform mass, but does not separate. Schwenke b has 

 some like erroneous observations as to the effect of heat. A moderate 

 warmth is not essential, though favorable, to the separation of the blood ; 

 it will take place at from 40-44. The effects of different temperatures 

 on coagulation are given in Notes in, xi, and xvi. 



a De Spont. Sang. Sep. Sect, i, cap. ii, b Haematologia, pp. 89-90, 8vo, Hag. 

 4to, Edin. 1760, in Sandifort. The- Com. 1743. 

 saur. t. ii. 



