ON THE PHYSIOLOGICAL ACTION OF NITRITE OF AMYL. 123 



less over the head. The eyes are also injected, aud occasionally fill with tears ; 

 the pupil slightly dilates, and over the suffused surface there is sensation of 

 heat, described by some as bixrning heat, and by others as mere tingling. 

 When these symptoms are at their height, a peculiar sensation is felt in the 

 head, a sensation of tightness across the forehead, of fullness, giddiness, and 

 prostration, but with no acute pain. The agent being taken away, the effects 

 cease rapidly. 



I have now witnessed these effects on more than two hundred occasions, 

 and have experienced them myseK forty times : I can pronounce them abso- 

 lute and valid phenomena, in no way dependent on mental exciteinent or 

 fancied excitement. They are nevertheless developed differently in intensity 

 in different persons, and they even slightly differ in the same person on 

 different occasions. I wUl give briefly two examples. 



On Mr. Kempton, a friend who has inhaled the vapour many times, the 

 effect on the heart is so rapid that it can be felt after the first three inhala- 

 tions. His pulse wiU rise from 72 to 105 in ten seconds, and he is conscious 

 of pulsation in every large artery in his body. His face becomes as red as 

 vermUion, and is not only subjectively but objectively heated. 



On Dr. Gibb, after inhalation a quarter of a miuute, the pulse rises during 

 the followiag quarter minute eight beats, and during the next quarter twenty 

 beats ; rising successively from 68 beats per minute to 76 and 88 ; the face 

 meantime becomes gTcatly siiffused, and giddiness is experienced. In both 

 the gentlemen named, the liiilse comes down to the natm-al standard in twQ 

 minutes after cessation of the inhaling process. On myself the symptoms 

 are almost identical with those presented by Dr. Gibb. 



In one instance I was so unhappy as to see the inhalation carried to the 

 extreme of danger. An incredulous friend seeing a bottle of the nitrite on 

 my library mantelshelf, during a minute in which I was absent from the 

 room, opened the bottle and commenced inhaling from the mouth. When I 

 returned I found him walking the library still inhaling, his face and neck red 

 as raw beef. In spite of all I could do, he would continue, till as he said he 

 felt some effect. While I was using forcible efforts to get the bottle from 

 him, he suddenly gave it me himself, and became speechless. I shall never 

 forget the gallop of that man's heart. As he leaned against a table, the 

 table vibrated and recorded visibly the pulsations. He panted for breath as 

 one who has run to the extremity : I could not get him to move reasonably, 

 and had the greatest difficulty in leading him into the open air. In a little 

 time the excitement declined, and was succeeded by depression and partial 

 loss of power ; but fortunately he slowly recovered, and I do not think he 

 was any worse for his misadventure : although, being a stout middle-aged 

 man, I feared that during the excitement some paischief might have happened 

 to the vessels of the brain. 



In the anxiety of looking after this gentleman, I did not count minute by 

 miuute the pulsations of the heart ; but the action was at one time IciO per 

 minute, and the violence was extreme : both sounds were lost, or rather they 

 occurred so qvdckly that the ear coidd not distinguish them, and the rapid 

 motion communicated a peculiar synchronous tremor to the upper limbs. 



My friend explained to me afterwards that his first sensation was that of 

 burning in the face, but that he thought this arose from laughing ; that the 

 next thing he felt, and which at length alarmed him, was the hearing the 

 pulsations of his own body very loudly and painfully. Then he felt a pecu- 

 liar powerlessness which could not be described ; but at no time did he lose 

 either sensation or consciousness. I estimated, from the loss in the bottle. 



