ON THE PHYSIOLOGICAL ACTION OF NITRITE OF AMYL. 121 



tissue of a whitey -brown colour, which in time became dark or dirty looking. 

 Decomposition of the tissue was, however, arrested, and I have several speci- 

 mens of a pathological character which have been thus preserved for six 

 months. 



In the extreme heat of the past summer, I placed in jars of equal size 

 two frogs that had recently died ; the jars were lightly covered with cloth 

 substance, and each one was covered to the same extent. Into one jar was 

 poured ten minims of the nitrite ; the other was left imtouched. The frog in 

 the jar that contained common air only was rapidly decomposing in six hours, 

 and on the following day was putrid. The frog in the jar through which the 

 nitrite was diffused in vapour was quite fresh three days after, and remained 

 fresh so long as the smell of the nitrite could be detected, showing that it had 

 not entirely evaporated. When the odour could no longer be perceived, 

 signs of putrefaction were observed in the animal, and these gradually ad- 

 vanced, but the change was very slow, and the body dried up at last rather 

 than putrefied. 



Ohservations. — Series 3. Si)ecimens of blood were drawn into open glass 

 vessels, containing proportions of nitrite varying from one to fifteen per cent, 

 in respect of the blood drawn. The blood thus charged coagulated in the 

 usual manner and in the natural space of time ; it became, however, of a dirty 

 red colour. Set aside in the open air, serum escaped from the clot ; but the 

 upper surface of the blood, instead of soon becoming of a bright red from the 

 absorption of oxygen, remained long dark. In proportion to the time of escape 

 of the nitrite the blood remained free from decomposition, and the i^eriod of 

 change in each vessel (five vessels were used) varied precisely according to 

 the degree with which the blood, while in the fluid state, was charged with 

 the nitrite. So long as there was distinct odour of the amyl-compound 

 there was no change. The tu-st sign of change, which even in the specimens 

 containing the lowest chiti-ge was never observed before six hours, consisted 

 in reddening of the upper surface of the clot ; then softening followed, decom- 

 position, and fluidity. In the heat of summer I found blood containing 

 fifteen per cent, of the nitrite remain unchanged for five days. The same 

 observations were made on simple albuminous fluids, on fluids from animal 

 cysts, and on saliva and certain other of the excretions. 



We gather from these experiments that nitrite of amyl, like chloroform, 

 alcohol, or other bodies to which reference has been made, arrests by its pre- 

 sence the change known as decomposition, preventing by catalysis the com- 

 bination of oxygen. That the nitrite itself remains tmdecomposed admits of 

 ready proof, because it can be re-collected ; and that it does not combine with 

 the structures or parts of the structures which it preserves, is shown by the 

 fact that the process of decomposition is set up only as the nitrite makes its 

 escape by evolution. 



Physiological Effects on liyhstg Oeganisms. 



Effects on the Skin. 



Ohservations. — Series 4. When nitrite of amyl is applied to the cuta- 

 neous human surface and held in close contact with it by being placed under 

 oiled silk or tinfoil, it produces after a brief period some injection of the vessels, 

 and a slight tingling sensation with heat. If the skin be prc^dously moist- 

 ened with water for a long time, the efi'eet of the nitrite is somewhat increased ; 

 but at no time is the action so rapid and marked as is that of chloroform or 

 turpentine. To test the relative poAvers of the nitrite and of chloroform, I 



