230 REPORT— 1870. 



watery vapour and carbonic acid in the lungs. The second, or direct method, 

 which consists iu agitating venous blood removed from the body vnih oxygen 

 or atmospheric air, and ascertaining the changes in temperature which would 

 then come into requisition. 



Claude Bernard (Comptes Eendus, 1856) ascertained the temperature of 

 the two sides of the heart by opening the internal jugular vein and the 

 carotid artery in dogs, and thinisting very delicate sell-registering thermo- 

 meters into the right and left cavities. He arrived at the conclusion that the 

 arterialized blood of the left side is invariably cooler than the venous blood 

 of the right side. Mr. Savory, in a paper entitled " On the relative Tempe- 

 rature of Arterial and Venous Blood," jwinted out that Claude Bernard's 

 method of experimenting was not free from fallacy, as by interfering with 

 the due action of the cardiac valves the thermometers would necessarily 

 induce some disturbance in the pulmonarj^ circulation. In his own experi- 

 ments Mr. Savory, having exposed the heat of dogs under the influence of 

 chloroform, punctured the right and left ventricles by means of a trocar, and 

 then introduced into the cavities delicate thermometers. By this method of 

 experimenting, he arrived at the conclusion that the blood of the left side of 

 the heart is invariably warmer than that of the right side. 



Very lately, in his work entitled " Lemons sur la Physiologic Comparee de 

 la Respiration," M. Paul Bert has published the results of his own experi- 

 ments, in which he introduced thermo-electric needles into the right and left 

 sides of the heart in the same manner as M. Claude Bernard had done. He 

 has confirmed the observations of Bernard ; his experiments are, however, 

 open to the same objections which were adduced by Savory against those of 

 the earlier observer. 



The second or direct method of research, to which I previously alluded, 

 consists in experimenting with venous blood removed from the body, and 

 ascertaining whether heat is evolved when it is agitated -^ith air or pure 

 oxygen. Although many authorities liave been quoted as maintaining the 

 opinion that when agitated with air venous blood is raised in temperature, 

 the only authors whose experiments are recorded are Dr. John Davy and 

 Mr. Savory. In his ' Eesearches, Physiological and Anatomical ' (vol. i. 

 p. 168), Davy attemijted to answer the question, " When oxygen is absorbed 

 by the blood, is there any production of heat ? " He agitated a mixture of 

 venous blood and metallic mercury in a glass phial with oxygen, and ob- 

 served that a rise in temperature always occurred. Curiously, Dr. Davy 

 does not appear to have considered that the rise in temperature must to a cer- 

 tain degree have been due to the agitation of the blood and mercury. Mr. 

 Savory, in the Monograph previously quoted, indeed found that by Dr. Davy's 

 method of experimenting no useful results could be obtained, as " in all 

 cases the increase of temperature seemed to be the result of the agitation." 



By shaking water in a similar manner with air, a small quantity of mer- 

 cury being present, I have often raised its temperature, though to a less 

 extent. 



Before commencing independent experimental researches, with a view to 

 determine, either by the direct or indirect method, the heat of artcrialization, 

 it appeared to me to be essential to undertake a set of experiments, with the 

 object of determining with accuracy the specific heat of blood; and it is to a 

 notice of these experiments that I confine my present Report, reserving the 

 account of the experiments now in progress on the fui'ther question of the 

 heat of artcrialization to a future Report. 



I believe I am quite accurate in stating that the specific heat of blood has 



