272 Drs. Fagge and Stevenson on Physiological Tests [May 18, 



of the practical question, whether it be possible to obtain the characteristic 

 effects of digitaline, not only from the extracts of liquids to which it had 

 been artificially added, but also from extracts of the stomach-contents and 

 vomited matters of dogs poisoned by that substance. The results of these 

 experiments were perfectly satisfactory ; and we think that our observa- 

 tions show conclusively that there is no difficulty in obtaining from these 

 complex mixtures physiological effects identical with those of a pure solu- 

 tion of digitaline. 



Far more difficult to decide than the question of practical applicability, 

 is the question aa to the theoretical accuracy and conclusiveness of the 

 physiological test for digitaline and the allied poisons. To this question 

 we do not venture to give a positive answer. Our experiments justify, as 

 we think, the hope that this test will be hereafter found of very consider- 

 able value in aiding in the detection of these substances; but it can be 

 only by the combined labours of many observers, and not merely by one 

 series of experiments, that this point can be finally settled. 



The following are the conclusions at which we have arrived, and which 

 are deduced from our own experiments in every instance, except where the 

 contrary is expressly stated, under heading 2. 



1 . Digitaline is one of a small class of substances of which the action 

 on frogs appears to be identical. As the heart is the organ primarily 

 affected by them, they may be called cardiac poisons, so far as frogs are 

 concerned. 



2. These substances are, besides digitaline, the Upas Antiar, the Hel~ 

 leborus viridis, and perhaps other species of Helleborus, the Tanghinia 

 venenifera, the Dajaksch or arrow-poison of Borneo, the Carroval and 

 Fao, South American arrow-poisons, and the Scilla maritima. Of these 

 we have ourselves experimented only with digitaline, antiar, the Helleborus 

 viridis and the H. niger, and the Scilla ; and we believe that we are the 

 first observers who have recognized the identity of the action on frogs of 

 the last of these plants with that of the other substances placed in this 

 group. Besides digitaline, only two of them, namely, the Helleborus and 

 the Scilla, are likely to be the subject of medico-legal investigation in 

 this country, and that but rarely. 



3. The characteristic effect of each of these agents on frogs is the pro- 

 duction of irregularity of the heart's action, followed by complete stoppage 

 of its pulsations ; the ventricle remaining rigidly contracted, and perfectly 

 pale, after it has ceased to beat ; the muscular power of the animal being 

 at this time unimpaired, and persisting as long as in frogs in which the 

 circulation has been stopped by other means, such as ligature of the heart. 



The irregularity in the heart's action, which precedes its stoppage, under 

 the influence of these poisons is peculiar. The rhythm is but little altered ; 

 and the beats are not necessarily diminished in number, as has been sup- 

 posed. Sometimes, however, the ventricle makes only one pulsation for 

 two of the auricles, the number of its contractions being therefore lessened 



