462 REPORT OF NATIONAL MUSEUM, 1893. 



came to us. I Avill try to make clear our methods and results. When a little of the 

 venom is placed in sutticient water it dissolves readily. If now we heat the solution 

 a coagulation takes place, just such as happens when white of egg hardens on boil- 

 ing. If by means of a filter we separate this substance, clotted by heat, it is found 

 to be mnocuous. The clear fluid which passes through the filter is, however, pois- 

 onous, but does not cause much local effect. As a whole the poison has been damaged 

 by heat, presumably becauseone or more of its ingredients had been injured by heat. 

 The next ste]) is to learn if the substance made solid and inert by boiling can not be 

 separated in some other way and in such a form as will leave it also poisonous. 



Allsoluble substances are divisible into two classes, one of which will pass through 

 an animal membrane into a current of pure water, and one of which will not. Those 

 which can so pass are said to be dialysable, and the filter is known as a dialyser, and 

 the process is called " dialysis." We disolve some of the poison in water and put it 

 in an inverted funnel, the Avide mouth of which, being covered with a thin animal 

 membrane is placed in distilled Avater. Under these circumstances the water goes 

 through the membrane, and dilutes the lluid above it and certain substances pass out 

 to the water. 



The matter which thus finds its way out to the water is said to be dialysable. 

 When examined it proves to be poisonous — to be uncoagulable by heat, and to be the 

 same as the matterleft unaltered when we boil the diluted poison for a few moments. 

 This substance resembles the albuminous matter which is formed when gastric juice 

 digests white of egg, and as the material so obtained is called peptone, we name our 

 product wliioh jiassed through the dialyser to water venom peptone. 



As the thinner Avater outers the dialyser and the peptone goes out within the vessel 

 there falls duAvn a white substance, which is easily redissolved if Ave add a little com- 

 mon salt. It falls out of solution because the salts belonging to A-euom and Avhich 

 keep the white matter dissolved are, like all saline substances, dialysable and i)ass 

 out along Avith the peptone. This white precipitate has certain likenesses to the 

 albuminous bodies known as globulin, and of which there are seA'eral kinds in our 

 bodies. That Avhich falls out of the solution of venom we named venom globuVni. 



The final results of Mitchell's and Eeichert's investigations were 

 embodied in a fine quarto volume published by the Smithsonian Insti- 

 tution in 188G as one of its " Contributions to Knowledge " under the 

 title "Researches upon the Venoms of Poisonous Serpents," to which 

 we must refer the reader for details. 



There are in those results, with regard to the chemical nature of the 

 venom, two points, however, to which I will call particular attention as 

 beingof a fundamental nature, and which the reader must keep steadily 

 in mind if he wishes to understand the present status of the question, 

 viz, first that the crotalus poison, as well as the cobra venom, consists 

 of several proteids, two of which are preponderating, although present 

 in a varying degree. One of these, the globulin, is not dialysable; the 

 other proteid, which passes through the membrane of the diaylser, 

 Mitchell referred to the peptones, though possibly it belongs to another 

 class, as will be seen later on. 



The second point is that these two chief constituents are present in 

 different proportions in the various i:>oisons, the globulin occurring 

 mostly in the crotalid snakes, but only in a minimal quantity in the 

 cobra. This difference in the composition of the venoms corresponds 

 markedly with the difference in the symptoms accompanying poisoning 

 by the Grotalidw (and the nearly related Viperidcv) on the one hand, and 



