8 THE TONER LECTURES. 



oxygen upon the blood and cut surfaces producing chemical 

 changes? Or, second, does the injurious action of the air de- 

 pend upon the presence of minute organisms floating in it, and 

 when brought into contact with cut sui'faces, acting like the 

 yeast-plant in the ordinary process of fermentation, and pro- 

 ducing irritation and decomposition of the organic elements of 

 the tissues with which they are brought in contact — in short 

 the so-called germ-theorj^ of putrefaction, fermentation, and 

 disease ? Third, is the mere contact of the air with divided 

 surfaces, but without external wound, sufficient to produce 

 inflammation ? Or, fourth, is it necessary that the continued 

 exposure to the air which external wounds generally involve, 

 should exist as an essential condition to the production of in- 

 flammation ? 



It would be impossible to enter at length into all the details 

 necessary to the solution of these questions, if indeed they 

 are j^et capable of solution ; but in reference to the first — I 

 may state in favor of the direct action of the 0x3' gen of the 

 air, and on the authority of the late Dr. Snow, so well known 

 for his early labors on the production of anaesthesia and the 

 action and administration of chloroform and other substances, 

 that, in a course of experiments performed by Jean Ingen 

 Housz, a Dutch physician, in the latter part of the last century, 

 it has been shown, that wlien a blistered surface is exposed to 

 nitrogen gas, the pain is diminislied, when exposed to the 

 atmosphere it is increased, and when exposed to oxygen gas 

 it is still further increased. Being desirous of verifying 

 these experiments, I agreed with Dr. Snow to repeat them, 

 and, on the 27th May, 1857, applied a blister, the size of a 

 half-crown, on the outer side of my left arm, and on the 28th, 

 the experiments were conducted by Dr. Snow, and the sub- 

 joined description written out by him from my account of the 

 effects produced by the gases and vapors employed. 



May 28, 1857: the cuticle was stripped off from the small 

 blister which had been raised in the arm, and the raw and 



