OF THE CALABAR BEAN. 769 



The inconsiderable elevation of temperature exhibited in these experiments is 

 probably an effect of the general muscular twitching that Calabar bean causes in 

 mammals. Tt is quite possible that it may be also in part the result of vascular 

 dilatation : but I think the first explanation is sufficient alone ; and this addi- 

 tional one seems improbable when we remember that during the dilatation the 

 circulation is extremely sluggish, because of the great diminution in the number 

 of the cardiac contractions that accompanies it. 



Action on the Blood. 



The blood obtained from animals that have been poisoned by Calabar bean 

 is generally dark in colour, because of the usual cause of death ; but if drawn 

 from the left side of the heart after a very large dose of the poison, it has the 

 scarlet hue of arterial blood. It frequently remains semifluid for some time, 

 and then clots loosely. When examined with the spectroscope, no modification 

 has ever been observed in the characters or positions of the normal crurine bands. 



In dogs and rabbits, the red blood corpuscles are changed in form, and present 

 various irregularities of outline, among which a well-marked stellar crenation 

 predominates. There can be no doubt that this is an effect produced by physo- 

 stigma, as I have frequently examined the blood previous to the administration, 

 and found its microscopic characters perfectly normal, and repeated the exami- 

 nation immediately after death, and invariably observed the above modifications. 

 No change is produced in the red corpuscles of birds or frogs, nor in the white 

 corpuscles of any animal I have examined. 



For the purpose of detecting any possible effect on the respiratory function of 

 the blood — a subject to which Harley, by his elaborate researches, has directed 

 considerable attention* — two experiments were performed, the results of which 

 agreed very closely. One of these may be given here, but without the numerous 

 details which are necessarily connected with it. 



Experiment LXV. 



A small quantity of blood was directly removed from the right side of the heart of a Skye- 



terrier dog, by passing a gum-elastic catheter down the right jugular vein, affixing a syringe 



with a stop-cock, and withdrawing the requisite amount, according to the ingenious method of 



Claude BEJtNAKD.-f- The catheter was then detached from the syringe, and, the stop-cock 



poison was administered, and apparently because of the constrained position in which it was neces- 

 sary to retain the rabbit. In other nine experiments of the same description, a similar fall occurred. 

 I endeavoured to find if a stationary, constant point could be obtained, after which the poison might 

 be given ; with the following result: — When the thermometer was introduced, the temperature was 

 97°; in one hour, it had fallen to 96°-3; in two hours, to 95°6 ; in three hours, to 95 3; in four 

 hours, to 94°7 ; in five hours, to 93° - 3 ; and in six hours, to 92°. The rabbit was now set free : it was 

 unable to stand ; and other four hours afterwards, it was found dead. As this is a very ordinary method 

 of treating rabbits during physiological experiments, it is important to recognise this injury to their 

 vitality, which may occasion many fallacious conclusions if overlooked. 



* On the Influence of Physical and Chemical Agents upon Blood ; with special reference to 

 the mutual action of the Blood and the Respiratory Gases. Phil. Trans. 1865, p. 687. 



-j- Action de 1 Oxyde de Carbon sur le Sang, Lecons, &c, 1857, p. 166. 



