de^ A(fens Physiques sur la Vie, 143 



Hifedium for the action of their nervous and muscular systems,^ 

 in their insulated state, the respiration and the circulation of 

 the blood being both suspendea. As a further corroboration 

 of the superior vivifying property of the air over simple 

 water, when the same animals were plunged into unaerated 

 water during a certain time, as soon as they were removed 

 into the atmosphere, they instantly revived ; and their ner- 

 vous and muscular systems were acted on according as they 

 were placed in either medium. Dr. Edwards also confirmed 

 the observation of Goodwin relative to the effect produced 

 on the colour of the blood. Properly speaking, the asphyxy 

 comes on the instant the air is excluded, the shades of dif- 

 ference in the colour of the blood being referrible to the air 

 left in the lungs after cessation of respiration. 



The next point to determine was the influence of the air 

 upon the same animals exercising the respiratory function, 

 and retaining their circulation, compared with those deprived 

 of these functions. 



. The difference of time in the two cases developes the 

 influence which the general circulation of the blood, free 

 from aerial contact, exercises upon the nervous system. 



To ascertain this point, an equal number of frogs, deprived 

 of the power to exercise their respiratory and circulating 

 functions, together with others left entire, were respectively 

 plunged into disaerated water. At times the difference in 

 favour of the untouched animals was twenty-four hours in 

 favour of the duration of life. Similar trials with toads and 

 salamanders produced the same results. In each case asfhyxy 

 came on ; but the existence of the animals which lived with- 

 out the respiration and circulation was much shortened. 

 Thus the relative powers of life between the sole and insu- 

 lated action of the nervous system, and its action combined 

 with the circulation of dark blood, were estimated. The 

 inference to be deduced, therefore, is, that although disae- 

 rated blood furnishes but an ephemeral sort of existence, it 

 nevertheless exercises a comparatively favourable influence 

 Upon the nervous and muscular systems, since it tends to the 

 prolongation of the action of these animal functions. 



Dr. Edv/ards next proceeds to investigate the phenomena 

 of asphyxy produced by strangulation, or the mechanical 

 obstruction to the access of air X6 the lungs, and consequently 

 to the blood. The same animals were employed. When^ 

 the windpipe was rendered impervious by ligature, the 

 muscles of the animals seemed to be paralysed directly ; and 

 though their motions became subsequently revived at times, 



