OF THE CALABAR BEAN. 787 



tinal movements are frequently increased in activity before death, and generally 

 continue for a considerable time afterwards. 



20. The pupil contracts in all cases of rapid poisoning in mammalians and 

 birds. The contraction may, however, be slight and of short duration; and 

 dilatation may then be observed during the greater portion of the experiment, 

 especially if the dose be a small one. Contraction of the pupil is produced in 

 frogs also. 



21. Calabar bean acts as an excitant of the secretory system; increasing the 

 action of the alimentary mucous, of the lachrymal, and of the salivary glands. 



22. In the frog, the symptoms of poisoning are not materially altered by 

 removal of the brain, or by division of the cervical portion of the spinal cord. 



23. Artificial respiration does not prevent death, in mammals, after the exhi- 

 bition of a poisonous dose. This is a necessary result of the effects of physostigma 

 on both the cerebro-spinal and sympathetic systems. 



24. Congestion of internal organs occasionally occurs ; but this is by no means 

 an invariable consequence of a fatal dose. 



25. The blood is generally dark after death, but becomes arterialised on 

 exposure to the air; its respiratory capabilities are unaltered; it often clots loosely 

 and imperfectly ; and, when examined with the spectroscope, the bands of scarlet 

 crurine are found unchanged. In the rabbit and dog, a microscopic examination 

 demonstrates an invariable change in the coloured corpuscles, which have their 

 outlines distinctly crenated. This change is not caused in the blood of birds or 

 amphibia. The white corpuscles remain unaltered. 



B. TOPICAL EFFECTS. 



1. When the poison is applied to the surface of a frog's brain, no effect is 

 produced ; but when it is brought into contact with the spinal cord, a few twitches 

 occur in the extremities, followed by paralysis of the portion of cord acted upon. 



2. When physostigma is applied to a mixed nerve-trunk, in a concentrated 

 form and with proper precautions to prevent absorption by neighbouring parts, 

 first the afferent nerve-fibres are paralysed, and afterwards the efferent. 



3. Topical application destroys the contractility of striped and of unstriped 

 muscular fibre. The heart's action is stopped by repeated application to its 

 external surface or to the pericardium. If a small quantity be injected into 

 one of its chambers, paralysis nearly immediately follows. 



4. The blood-vessels are dilated when a solution is applied to the web of the 

 frog's foot. 



5. The effects of the application of Calabar bean to the eyeball are a some- 

 what painful sensation of tension in the ciliary region, contraction of the pupil, 

 myopia and astigmatism; with, frequently, congestion of the conjunctival vessels, 

 pain in the supra-orbital region, and twitches of the orbicularis palpebrarum 

 muscle. 



VOL. XXIV. PART III. 10 D 



