718 DR FRASER ON THE PHYSIOLOGICAL ACTION 



drops of distilled water and applied to the conjunctiva of a white rabbit, in the presence of my 

 friend, Dr Crum Brown. Before the application, both pupils had a diameter of Jfths of an 

 inch, in a full light. At first a little irritation was caused. In thirteen minutes, the pupil 

 had contracted to /o-ths, and in eighteen minutes to s%ths ; the other pupil still remaining at its 

 original diameter of |f ths. This extreme contraction continued for upwards of an hour ; but 

 in two hours the pupil was 6 Vths, and by the following morning it had resumed its original 

 diameter. 



It would, therefore, appear that physostigma, when administered by a vein, 

 finds its way into the stomach — a method of poison-excretion which has been 

 established in the cases of antimony and arsenic. 



Although this investigation has for its principal aim the determination of the 

 exact method in which physostigma acts, and the demonstration, as far as 

 possible, of the histological structures which it influences, it may be necessary to 

 describe, at this place, the general symptoms which follow the administration of 

 a poisonous dose. In the case of mammals, I have already entered fully into this 

 subject in a previous paper, from which I extract the following descriptions :* — 



" When a small fatal dose is administered to one of the lower animals, a train 

 of symptoms is produced usually in the following order : — A slight tremor is first 

 seen, especially at the posterior regions, and this extends forwards to the anterior 

 extremities and the head. The limbs yield immediately afterwards, the posterior 

 becoming generally first paralysed, and the animal lies extended in a state of 

 almost complete muscular flaccidity. A few attempts may be made to recover 

 the normal position, but they are usually ineffectual. The bowels, in most cases, 

 are evacuated, and urine is passed. The pupils generally contract; as the 

 symptoms advance, the respiration becomes slow and irregular, with a distinct 

 stertor accompanying both inspiration and expiration, and frothy mucus escapes 

 from the mouth. Muscular twitches occur, and often continue after respiration 

 has ceased. Reflex action cannot be produced by either pinching or pricking 

 the skin. By-and-by the eyelids do not contract when touched or even when the 

 eyeball is pricked. On lifting by the ears, the limbs hang inertly, and the only 

 sign of life is an occasional gasping inspiration, which also soon ceases, and the 

 animal appears dead. 



" Consciousness is preserved during the whole time, until the power of expres- 

 sion is lost. During incomplete paralysis, proofs of sensation may be obtained by 

 pinching the ears or pricking the sign. Immediately after death the pupils dilate. 



" On opening the body the various muscles which are cut contract. The 

 diaphragm and muscles of the extremities may be excited to action by pinching 

 the phrenic and sciatic nerves, and the contractility of the muscles generally is 

 retained for some time after death. The heart is found acting regularly, and the 

 intestines exhibit distinct vermicular action. The heart may continue its action 



* Op. cit. sect. ii. 



