POISOXOUS ACTION. 41 



are discharged, and when the intestinal canal is completely 

 emptied, the diarrhaa becomes serons, the expelled matters 

 being liquid, blackish, and of a repulsive odour. The skin 

 becomes icy cold, the, thermometer introduced into the mouth, 

 rectum, or subcutaneous cellular tissue standing in some cases 

 at 31'5° C, or even before death at 25° C. Death generally 

 comes on quietly, but is sometimes accompanied by uncon- 

 nected movements. 



Wlien given in doses less rapidly fatal, so that each dose 

 would only produce slight symptoms, which would soon pass 

 away if the dose were not carefully repeated, the influence 

 which it exerts on the circulation is by far the most pro- 

 minent phenomenon. At first there is slight excitement of the 

 heart, and its pulsations are a little quickened, then, later on, 

 they undergo a remarkable diminution, falling to 25 or even 

 20 per minute. If the dose be still repeated, the beats become 

 quicker and more energetic, rising to 55, 60, 65, and 70. The 

 cardiac sounds are more clearly heard, more distinct from each 

 other than normally, and following a different rhythm, there 

 being occasionally intermittences, usually after the same number 

 of beats, but this number varying in different subjects, and in 

 the same subject according to the date of the poisoning. There 

 may be five or six pulsations between the intervals in some, 

 15 or 16 in others, and in yet others the intermissions are com- 

 pletely irregular. As the poisoning goes on, metallic ringing 

 appears, and becomes more and more distinct and sonorous. 

 Still later, a vibratory thrill appears, and is followed by a bellows 

 murmur. As death approaches the beats of the heart become 

 more and more rapid, being 92, 100:, or even 114. The beats 

 of the pulse correspond in time to those of the heart ; but as the 

 latter increase in energy, in the same ratio the former become 

 more and more feeble, arid less and less perceptible, till at 

 last, when poisoning is complete, it becomes completely imper- 

 ceptible. 



In doses so small as to have no poisonous effect, its action is 

 shown first on 'the urine and secondly on the circulation. To 

 show this, Messrs. Bouley and Eeynal give the following 

 typical case: — 



