154: KEPOKT — 1871. 



supplied -with abundance of air, and well protected from cold. The intro- 

 duction of the vapour was so moderated that the same quantity was made 

 to undergo diifusion each day. 



The first fact that became well established was, that cold and a low baro- 

 metric pressure greatly assisted the action of the vapour, and frequently led 

 to sudden death from congestion of lung and accumulation of fluid in the 

 bronchial tubes. 



A second fact, of singular interest, was the degree to which recovery from 

 extreme congestion of lung would take place, on simply withdrawing the 

 animal from the influence of the agent. A\Tien the lungs were so obstructed . 

 that what is called rale fi'om accumulation of mucous fluid in the bronchial 

 surface was most marked, there was invariably a rapid recovery on removal 

 to fi-esh and warm air. 



A third fact relating to the lesions induced, beyond mere congestive lesions, 

 is also of deep interest. The lesions were primarily all of one kind ; they 

 were hjemorrhagic, and consisted of red spots and patches, in which blood 

 was effused and coagulated in the connective tissue. The position of the 

 hsemorrhage was singular. In three cases it was only in the extreme point 

 of the apices of the lungs ; in four other cases lower portions of lung were 

 involved, but in these the apices were the seats also of haemorrhagic disease. 

 It would appear, in fact, as if these points of lung were least resistant to the 

 force of the circulation. 



In the animals observed these distinct haemorrhagic changes were usually 

 fatal, so that the further result of the local neural paralysis could not be 

 carried out as could be wished. In two cases, nevertheless, we had other 

 results worth recording. 



In one instance there was clearly an oedema of the lung structure : in 

 another the pleural membrane was raised in four or five granulated points, 

 round each of which there was efi'used blood. Dr. Sedgwick, who took the 

 lungs of this animal for careful microscopic inspection, reported to me that 

 there were plastic exudations in various parts of both lungs, and that the 

 granulations of which I have spoken consisted of effused plasma beneath 

 the pleura. 



I am well content to leave these observations as I have written them 

 above, with but two observations more. It has been suggested by an 

 accomplished and acute English physician. Dr. Eado, of Norwich, that 

 pulmonary consumption may be primarily due to pulmonary vascular para- 

 lysis. My experiments do not enable me at this stage to endorse Dr. 

 Eade's hypothesis as to the primary origin of consumption, but certainly 

 they indicate to what extent nervous deficiency wiU go in favouring the 

 hemorrhages, congestions, and exudations which attend tubercular disease. 



The concluding observation this year with nitrite of amyl relates to the 

 fact that the nitrite atmosphere, when it is not too much charged Avitli 

 the vapour, exerts a certain curative efiect. Three rabbits were brought to 

 me with a skin disease resembling lepra in man. They were emaciated and 

 feeble, the fur on the back along the whole length of the spine had been cast 

 oil, and the skin was covered over this part with white asliy scales. 



Placing these animals in an atmosphere of nitrite of amyl, I noticed that, as 

 the agent took effect, the scaly white skin on the back became red and 

 flushed. In a day or two the scales disappeared, the fur began to extend, 

 and the general health to improve. In a month all the animals had entirely 

 recovered. 



There are many local conditions of disease in man and other animals in 



