ON HEAT GENEKATEl) IN THE BLOOU. 139 



capacity of eight liquid ounces, was selected and earefuUy enveloped in bad 

 conducting substances, viz. several folds of flannel, of fine oiled paper, and 

 of oiled cloth. Thus prepared, and a perforated cork being provided holding 

 a delicate thermometer, 2 cubic inches of mercury were introduced, and im- 

 mediately after it was fiUed with venous blood kept liquid as before described. 

 The vial was now corked and shaken ; the thermometer included was sta- 

 ■iiouary at 45°. After five minutes that it was so stationary the thermometer 

 ■was withdrawn ; the vial, closed by another cork, was transferred to a mercu- 

 rial bath, and Ig cubic inch of oxygen was introduced. The common cork 

 was retui-ned, and the vial was well agitated for about a minute : the ther- 

 mometer was now introduced ; it rose immediately to 4G°, and, continuing 

 the agitation, it rose further to 46°-5, very nearly to 47°. This experiment 

 was made on the 12th of February, 1838, on the blood of the sheep. On the 

 following day a similar experiment was made on the venous blood of man. 

 The -sial was filled with 11 cubic inches of this blood, its fibrine broken up in 

 the usual manner, and with 3 cubic inches of mercury; the temperature of 

 the blood and mercury was 42°-o, and the temperature was the same after 

 the introduction of 3 cubic inches of oxygen. The temperatui-e of the room 

 being 47°, a fire having shortly before been lit, the vial was taken to an ad- 

 joining passage, where the temperature of the air was 39°. Here the vial 

 was well agitated, held in the hand with thick gloves on as an additional 

 protection ; after about three quarters of a minute the thermometer in the 

 vial had risen a degree, viz. to 43°'5." Dr. Davy relates two other experi- 

 ments, of which the first Avas performed on the venous blood taken from the 

 jugular vein of a sheep, the second on arterial blood. The three experiments 

 with venous blood showed that when agitated with mercury and air for the 

 space of a minute, venous blood was heated to the extent of 1° Pahr., whilst 

 the arterial blood was heated only half a degree. 



Dr. Davy quotes Sir Charles Scudamore, who, in his ' Essay on the Blood,' 

 at p. 59, states that venous blood cools much more slowly in oxygen gas than 

 in atmospheric air ; that the same blood divided into two cupping-glasses, 

 " after an interval of eight minutes from the beginning of the experiment," 

 exhibited a diff'erence of 8°, — that exposed to oxygen being 85°, that to atmo- 

 spheric air 77°. 



H. Nasse, in his article on Animal Heat in the fourth volume of Wagner's 

 * Handwiirterbuch der Physiologic' (1842), quotes Marchand to the effect 

 that when oxygen is shaken with blood the latter is heated. 



In a paper entitled " On the lielative Temperature of Arterial and Yenous 

 Blood," Mr. "W. B. Savory, having described at considerable length observa- 

 tions on the temperature of the two sides of the heart, describes others 

 performed with a view to check the accuracy of the experiments of Dr. 

 John Davy, and states the conclusions to which he was led by his own 

 experiments, viz. : — 1st, that when venous blood is treated, as was done by 

 Dr. Davy in his experiments, with oxygen, its temperature was usuaU}- raised 

 from 1° to 1|° or 2°; 2ndly, that when venous blood was treated in a similar 

 manner with hydrogen or carbonic acid, its temperature was as frequently 

 raised, and generally to the same extent ; 3rdly, that similar experiments 

 upon arterial blood usually jdelded the same results ; 4thly, that in all cases 

 the increase of temperature seemed to be the result of the agitation. In 

 concluding his paper, Mr. Savory remarked, " At present there is no evi- 

 dence upon which we can safely venture further into this inquiry. If, as I 

 conclude from my experiments, arterial blood is warmer than venous, the 

 increase of temjierature must occur in the lungs as a resvilt of those changes 



