4 THE TONER LECTUiiJiS. 



instances the unconsciousness was developed verj' suddenlj-. 

 In either case death was finally brought about by paralysis of 

 respiration or apnoea. A thermometer plunged into the brain 

 directly after death indicated a temperature of 113° in a cat, 

 and of 111° F. in a rabbit. In a second series of experi- 

 ments the skull was opened, and the thermometer placed in 

 the brain so soon as there was decided coma. The brain tem- 

 perature under these circumstances in the cat was determined 

 to be about 108° F. As in these experiments it was found 

 that pouring cold water upon the head at once relieved the 

 coma, the conclusion is logically irresistible that the coma 

 was produced by the heat. The degree of temperature at 

 which, in the locally heated brain, consciousness was lost, 

 and at which death occurred, was found to closely correspond 

 with the degrees at which the same phenomena occurred when 

 a general augmentation of the bodily heat was produced by 

 exposure to the sun, or to artificially heated air. 



It having been determined that heat applied to the brain of 

 an animal is capable of causing cerebral symptoms similar to 

 those seen in fever, the next point to be studied is the action 

 of the same force upon the heart. 



In an admirable paper on this subject* Dr. T. Lauder Brun- 

 ton has collected the evidence, and repeated the experiments 

 so thoroughly, that it is unnecessaiy here to discuss the 

 matter at length, and I shall content myself with stating the 

 chief facts ; referring the reader to Dr. Brunton's paper for the 

 proof. When the cut out heart of a frog is exposed to a 

 rising temperature, the cardiac jxilsations constantly become 

 more and more rapid until a heat limit is nearly reached, at 

 which the action of the heart ceases. The increase in the 

 rapidity of the movements of the heart is not in direct relation 

 to the increment of temperature; at first the increase ofmove- 



* St. Bartholomew's Hospital Reports, vol. vii. 



