56 REPORT — 1867. 



perature in chambers of the same size, and administered the same doses of 

 chloroform and of the tetrachloride of carbon. Pigeons and rabbits alike 

 gave evidence of the more severe effects of the Inttcr substance. In this opi- 

 nion my friend Dr. Sedgwick, who has rendered me the most valued aid in 

 these inquiries, entirely coincides. 



The Bichloeide of Methtlexe. 



The last compound on our list is of great interest, from the circumstance 

 that it promises to be a new and valuable anaesthetic. In experimenting 

 with chloride of methyl in ether, I was so struck with its good action that I 

 asked Mr. Bobbins, the chemist who has prepared the compounds for me, to 

 endeavoiu' to find a more stable compound, having similar physical properties, 

 from the methyl series. In a few days he brought me the fluid I now place 

 before the Section, made for him by Dr. Versman. This fluid is the bichlo- 

 ride of methylene. It is formed by the action of nascent hydrogen on 

 chloroform, and it differs from chloroform in that one atom of chlorine is re- 

 placed by an atom of hydrogen. Its boiling-point is 88° Fahr, and the odour 

 of its vapour is sweet and much like that of chloroform. On testing it phy- 

 siologically I found it to be a gentle and perfect general anaesthetic. Under 

 its influence animals lapse into the third stage of anassthesia, with the 

 slightest exhibiton of the stage of excitement. The insensibility is deep and 

 weU sustained, and the recovery quiet and good. [Dr. Eichardson liero 

 showed an experiment of putting a pigeon into a deep sleep.] In some 

 experiments, in order to see the extreme effect, I have carried the adminis- 

 tration to the extent of arresting the phenomena of life. I have thus learned 

 that the respiration and circulation, under the last action of this agent, cease 

 simultaneously, and that the muscles retain their ii-ritability for even an 

 hour after death. The lungs are left M'ith blood in the respiratory circuit, 

 both sides of the heart are charged with blood, and the blood itself remains 

 unaltered in physical property. Compared with other antesthetics, the bichlo- 

 ride of methylene appears to me to combine the anaesthetic power of chloro- 

 form with the safer properties of ether. It is too early to speak positively on 

 this point, but if the expectation be fulfilled, the perfection of a general 

 anaesthetic will have been obtained for the benefit of the world. And, even 

 should this happy result not be accomplished, the way at least is paved to- 

 wards the discovery of some intermediate body wliich shall answer to the re- 

 quired jDhysical demand. 



In renewing all the facts connected with the physiological action of the 

 methyl series, w"e gather that, according to their composition, they exert cer- 

 tain definite influences on different parts of the nervous organism. The oxide 

 produces an influence of its own, that of slowly paralyzing the motor func- 

 tion before destroying common sensibility. The nitrite and nitrate rapidly 

 paralyze the centres of motion; while the chloride, the iodide, and the bromide, 

 together with the substitution chlorine compounds, not only paralyze motion 

 but also destroy sensation. I conclude this Eeport with one other observa- 

 tion. At first sight it may seem that the isolation of the phenomena pro- 

 duced by special agents, and the discovery of a new antesthetic are sufficient 

 characteristics of this research. "With every respect, I submit that a broader 

 question is involved. At the Meeting at Birmingham I suggested, almost 

 with a feeling of fear, that out of these studies might spring up a fixed prin- 

 ciple of therapeutical discovery. Now I have the conscious happiness of 



