786 DR FRASER ON THE PHYSIOLOGICAL ACTION 



11. Division of the pneumo-gastric nerves, or their paralysis by curare, or 

 destruction of the medulla oblongata or spinalis, does not protect the heart 

 from the action of physostigma. 



12. The lymphatic hearts of frogs poisoned by Calabar bean soon cease to 

 contract. 



13. In rabbits, a large dose paralyses the cervical sympathetic nerves, before 

 the death of the animal. A smaller fatal dose merely diminishes their activity. 



14. Before the stoppage of the heart, proofs may be obtained of the vitality of 

 its sympathetic ganglia ; but, as striped muscle is not affected by Calabar bean 

 conveyed by the blood, we are obliged to infer from the symptoms respectively 

 produced, that the activity of the cardiac sympathetic system is probably 

 destroyed by a large dose, and lessened by a smaller one. 



15. The animal temperature, both external and internal, has been invariably 

 observed to rise in rabbits and dogs, but only slightly and for a short period ; after 

 which it slowly falls. 



16. The condition of the capillary circulation was examined in the web of the 

 frog. Soon after the exhibition of the poison, the smaller arteries and veins con- 

 tracted slightly; but, after a short interval, this contraction was succeeded by a 

 rapid and permanent dilatation, in which the calibre of the vessels was consider- 

 ably above their maximum previous to the poisoning. This capillary dilatation 

 appears to occur all over the body, as is shown by a peculiar blue coloration of 

 the voluntary muscles and of the heart, a similar coloration of the serous and 

 fibro-serous tissues, and a congestion of the blood-vessels in the conjunctiva and 

 iris. This change also occurs, in a less marked manner, in birds and mammals. 



17. The general results of experiments in which the arterial and venous ten- 

 sions were examined were, that the arterial tension first diminished slightly, 

 immediately after the administration of the poison, then gradually increased until 

 it reached its maximum — when the number of cardiac contractions had diminished 

 to at least one-half, — and afterwards rapidly fell ; and that the venous tension 

 began to increase immediately after the administration, continued doing so until 

 it slowly reached its maximum — when the arterial tension had considerably 

 diminished,— and then fell, though more gradually than the tension of the arterial 

 system. The number of the cardiac contractions when the venous tension had 

 attained its maximum, was about one-third of the average before the poisoning ; 

 the respirations were rather less frequent than before, and the temperature had 

 risen a few tenths of a degree. 



18. Physostigma causes extreme diffusion in the pigment-cells of the frog's 

 skin, and thus a very marked change occurs in the colour of the animal during 

 the progress of the symptoms. 



19. In dogs, the peristaltic action of the intestines is usually destroyed at 

 death ; it may, however, continue a short time afterwards. In rabbits, the intes- 



