4 PROPERTIES OF 



ing, that it increased the disposition to coagulate; for the 

 blood in the cup and in the phial was not only congealed, but 

 the separation was much advanced before the whole of the 

 blood in the basin was coagulated. Thence I am led to con- 

 clude, that the separation of the blood in a given time, is in 

 proportion as the heat in which it stands is nearer to the 

 animal heat, or 98 ; or greater in that heat than in any of a 

 less degree (m). And I am confirmed in this inference by 



(in.) Mr. Hewson has clearly shown that a high temperature pro- 

 motes and a low one retards coagulation. Mr. Hey a says, that a heat 

 equal to that of the living body is most favorable to the separation of 

 the serum and clot; and Professor Burdach, b quoting Hewson, Schrceder, 

 and Thackrah, asserts that this heat is most favorable to coagulation. 

 But it would appear to be more hastened by a higher temperature. In 

 Hewson' s experiments vi-ix, blood in the veins just removed from dogs, 

 coagulated completely at 120- 125 in eleven minutes, remained fluid 

 after that time, when the heat was not raised above 114; and when kept 

 at rest in the vein in the living animal was not wholly coagulated in 

 less than two or three and a quarter hours. Mr. Hunter found that 

 blood removed in sections of the jugular veins from dogs, and heated to 

 about 120, coagulated five minutes sooner than when kept at its 

 natural heat ; and that the contraction of muscle was hastened by a tem- 

 perature of 125 and of 98. In Mr. Thackrah's experiments/ blood 

 removed in the jugular veins from living dogs, did not coagulate at the 

 atmospheric temperature in twenty minutes, nor in an hour at 98-100 ; 

 and blood, in portions of the umbilical cord, detached from a living 

 child, and placed in water at 100-110, was fluid and of the natural 

 consistence at the end of fifteen minutes, and found to contain clots after 

 thirty-five minutes. Of blood abstracted as usual, he believed thai a tem- 

 perature of 120-130 considerably hastens coagulation; and that 100-1 10 

 generally does so, but in a less marked manner. Sir Charles Scudamore" 

 found that blood drawn from a person affected with pleurisy coagulated 

 quicker at 120 than at 98. Dr. Davy's experiments f dispose him to 

 infer that a heat of 120 immediately renders the blood more liquid 

 and accelerates coagulation ; that it is rather retarded than quickened 

 at 100; more rapid at 80 or 90 than at 100, and less so than at 

 120. Mr. Hunter^ observed that a cup of blood put into water at 

 150 coagulated much quicker than at 48, whence he infers that heat 

 acts as a stimulus upon the blood, adducing the experiment "as one of 

 the proofs of the living principle of the blood, where it is contrasted 

 with a similar experiment on living muscles." Mr. Prater 11 says, that 

 blood is kept permanently fluid by a heat of 140-150. 



The following is a brief synopsis of my own experiments. Fahrenheit's 



a Obs. on the Blood, p. 39. e On the Blood, p. 20, 8vo, Lond. 1824. 



b Physiologic, tr. par Jourdan, t. vi, p. 45. f Res. Phys. and Anat. ii, 78. 



c Works, ed. by Palmer, iii, 26, 110. s Works, ed. by Palmer, iii, 144. 



d On the Blood, ed. 1834, Exp. 44, 45, 50, h Exp. Inq. in Chemical Physiol. Part i, 

 &1, 52, 56. pp. 12 et seq. & 73, 8vo, Lond. 1832. 



