720 DR FRASER ON THE PHYSIOLOGICAL ACTION 



Action on the Voluntary Muscles. 

 The peculiar successive tremors, which are observed in warm-blooded animals, 

 at first sight suggest that the paralysis caused by Calabar bean is due to an affection 

 of the muscular system ; and the condition of general flaccidity, which so rapidly 

 follows its administration to frogs, appears to favour, as it certainly does not con- 

 tradict, this opinion. Without pretending that such was the order followed in 

 this investigation, it will, as a matter of convenience, be advisable to examine, in 

 the first place, the effects which are produced on voluntary muscles. 



Experiment IV. 

 A full-grown active rabbit had injected into the subcutaneous tissue of its right flank, three 

 grains of extract, suspended in eleven minims of distilled water. Tremors occurred in two 

 minutes ; the anterior extremities soon after yielded ; and, in four minutes and thirty seconds, 

 the animal fell, the muscular trembling having increased in vigour and having become general 

 over the body. Eespiration ceased in five minutes after the injection, but muscular tremors 

 continued during other three minutes. "When the thorax was opened the heart was found 

 dilated and passive. Twenty-four minutes after the administration, galvanic stimulation of the 

 sciatic nerves caused powerful muscular contractions ; within thirty-six minutes, these nerves 

 were completely paralysed, though application of the electrodes to any of the voluntary muscles 

 produced marked contractions. These contractions became gradually weaker, but could be dis- 

 tinctly excited until one hour and thirteen minutes after the poison had been exhibited. 



The general result in all the other experiments which Avere performed on 

 warm-blooded animals was the same. Muscular contractility remained after 

 destruction of the function of motor nerves ; and this also occurred, in even a 

 more marked manner, with frogs. 



Experiment V. — {Temperature of Laboratory about 53° F.) 



By means of Wood's syringe, I injected three grains of extract, in fifteen minims of distilled 

 water, into the lower portion of the abdominal cavity of a frog which weighed 473 grains. The 

 usual phenomena quickly occurred. In sixteen minutes, the sciatic nerve and the neighbouring 

 muscles of the left thigh were exposed and found active. 



The muscles were now of a very blue colour, quite distinguishable from their normal appear- 

 ance ; and this colour change was discovered in the serous and fibro-serous tissues also. In about 

 four hours, motor nerve-conductivity was universally destroyed. The heart contracted rhythmi- 

 cally, and at a very reduced rate, until twenty-six hours after the administration, after which, the 

 auricles contracted more frequently than the ventricles, and continued to do so until the heart's 

 action ceased, seventy-three hours after the poison was injected ; and, by microscopic examina- 

 tion of the web, it was found that a more or less feeble circulation M r as all this time maintained. 

 Until this stage, no apparent change occurred in the readiness and vigour with which the 

 striped muscles contracted when directly galvanised ; their reaction continued to be alkaline, 

 and they were perfectly flaccid. Soon after the stoppage of the heart's action the blue 

 colour, which has been already mentioned, began to disappear, and in ninety-six hours (four 

 days) the muscles were quite pale. No stiffness was yet observable, and galvanism ^till induced 

 faint contractions. Rigor mortis commenced soon after this, but its progress was extremely 

 slow, as galvanism produced dimples at the electrodes until 110 hours. When the frog was 

 again examined, at 129 hours after the injection of physostigma, no muscular contraction could 

 be produced by powerful galvanism ; rigor mortis was complete ; and the reaction of the muscles 

 was found to be acid. Galvanism could produce a very faint contraction of the cardiac muscle, 



