xlix 



animals, and the circulatory apparatus which gives the basic condi- 

 tions of nutrition in the higher animals, occupy his mind in the first 

 two Essays. In the second he was aiming at the solution of one 

 part of the question of questions for physiologists, how poisons ope- 

 rate on vital organs so as to produce death. These, his first papers, 

 were composed with great clearness, and based on well-devised expe- 

 riments. They do not exhaust subjects then only opening ; for they 

 have both been carried forward by various able inquirers in the half 

 century that has now elapsed since he wrote them. But Brodie 

 proved the correctness of the opinion advanced by Bichat and Cruick- 

 shank, that the cessation of the heart's action depends, not directly 

 on abstraction of the influence of the brain, but on the cessation of 

 respiration ; and he showed that, to some extent (though to what 

 extent and in what way is not even now certain), the maintenance 

 of animal heat is under the influence of the nervous system. The 

 most important of his experiments on poisons were those which he 

 made with the Woorara. They showed that the poison is first absorbed 

 through the blood-vessels, and so acts on the nervous system ; that in 

 consequence of the paralysis thence ensuing, the respiratory organs 

 cease to act ; and that the failure of respiration leads to cessation of 

 the heart's action, and suppression of the circulation. Accordingly it 

 was further shown that if respiration be artificially performed, the heart 

 will continue to act, and the blood to circulate ; and that if the process 

 be carried on for a sufficient length of time, in some instances the 

 brain will recover, and life will be maintained without perceptible 

 impairment. 



Brodie appears also to have been the first to show that the 

 Antiar poison of Java operates by primarily arresting the action of 

 the heart, and that it thus offers a remarkable contrast to the class 

 of poisons to which the Woorara belongs. 



The Copley Medal was awarded to Mr. Brodie for the former set 

 of observations in the year 1811. 



It is noteworthy that at this period he was an active member of 

 two small societies, to one of which, the Animal Chemistry Club, 

 Humphry Davy belonged, while of the other, the Society for the 

 Promotion of Medical and Chirurgical Knowledge, John Hunter had 

 been one of the original members. He began about this period to 

 be a frequent visitor at Holland House j ajid he has often been heard to 



VOL. xn. d 



