286 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



most constant are fibrillar tremblings, a general congestion 

 of the superficial vessels, stupor, and especially the tetani- 

 form contraction of the muscles of the abdomen. 8. Nicotine 

 is one of the poisons the effect of which is most speedily dis- 

 sipated, and the habituation to which is soonest accomplished. 

 9. Contrary to what has generally been assumed, the vapor 

 of nicotine at the ordinary temperature is not dangerous, but 

 it is quite otherwise if the liquid is carried to ebullition. It 

 then produces palpitations, a decided suffocation, precordial 

 pain, and vertigo. Smaller animals exposed to this vapor 

 die almost instantaneously. 10. Among the effects of tobac- 

 co-smoke upon man may be mentioned, in small doses, excita- 

 tion of the intellectual faculties for the moment; in repeated 

 doses it produces palpitations, troubles of vision, and more 

 especially a decrease of the memory, and particularly the 

 memory of words. 1 i?, May, 1872, 93. 



ACTION OF ANAESTHETICS ON THE NERVOUS CENTRES. 



M. Prevost, in the course of some experiments in reference 

 to the mode of action of anesthetics and chloroform upon the 

 nervous centres, has reached conclusions quite different from 

 those of Claude Bernard. This physiologist asserts that 

 chloroform, in acting upon the brain, causes anaesthesia not 

 only in this organ, but acts also at a distance upon the spinal 

 marrow, without being in contact with it. 



M. Prevost has repeated the principal experiments of Ber- 

 nard, which consisted in stopping the circulation of the blood 

 in frogs by a ligature beneath the axillae, then injecting chlo- 

 roformed water in some beneath the skin of the anterior 

 portion of the trunk, and in others beneath the skin of the 

 posterior portion. By varying the position of the frogs in 

 these experiments, Prevost found, contrary to the opinion of 

 Bernard, that chloroform introduced into the hind quarters 

 produced anaesthesia in the anterior w T hen the frog is placed 

 with the posterior limbs in the air, while chloroform intro- 

 duced into the fore quarters does not produce anaesthesia in 

 the hinder if care has been taken to place the frog with the 

 head downward. He thinks, therefore, that M. Bernard has 

 not been sufficiently guarded against the filtration of chloro- 

 form across the tissues. 



Upon applying pure chloroform upon the denuded brain 



