INDUCTION OF ANAESTHESIA. 33T 



alter tlie velocity of the circulation, but constant currents do. 

 ])uring the time they are passing, both the rapidity of the 

 current and the size of the kidney increase, and after the 

 irritation ceases they diminish. When the circulating blood 

 contains a small quantity of chloral, this action is altered. At 

 first, when the chloral has not altered the current much, it 

 becomes slightly diminished during the irritation, and slightly 

 increased after its removal. When the chloral has acted 

 longer and increased the velocity of the current to five or six 

 times its normal, no alteration is noticed during the application 

 of the current, but a still further increase occurs after its 

 removal. 



After the kidney has been removed from the body for 24 

 hours, and kept in a cool place, its vessels still retain their 

 irritability, but small doses of chloral in such a kidney only 

 cause contraction, and larger doses of 0*3 to 0*5 per cent, are 

 requisite to induce dilatation. The effect is not due to the 

 action of the chloral on the blood, for it is produced when the 

 blood is replaced by serum. One of the most extraordinary 

 things about the action of chloral is that, in the dead kidney, 

 instead of increasing the rapidity of the current, or leaving it 

 unaltered, chloral greatly diminishes it — exactly the opposite to 

 its effect on the living organ. When the blood used in the 

 artificial circulation is saturated with carbonic acid, chloral no 

 longer produces any effect on the vessels, so its action would 

 seem to be abolished by this gas. 



Induction of Anesthesia. — At p. 257 I have stated that 

 chloroform is inadmissible as a narcotic, as its administration 

 seemed to cause dogs so much pain, but farther experience has 

 shown me that this statement is incorrect. Chloroform can be 

 readily administered to all animals by placing them under a 

 glass bell-jar, along with a sponge or piece of blotting-paper, 

 saturated with the anaesthetic. The advantage of the glass jar 

 is that the movements of the animals can be distinctly seen, 

 and they can be removed immediately on their becoming 

 insensible, thus avoiding the danger to which they would be 

 exposed by longer inhalation of air saturated with the vapour. 

 The vapour being heavier than air sinks to the bottom of the 



z 



