154 THE TENOMS OF CERTAIN THANATOPHIDEJ3. 



venom-globulins together, etc, and then form our conclusions. The latter course 

 seemed preferable : first, because of the similarity in the actions of all pure venoms 

 and of the ready interpretation of any differences, and of the resemblance in the 

 actions of members of each of the classes of poisons ; second, because in some of 

 the actions such diverse factors are at work as to give apparently contradictory 

 results, so that conclusions founded upon a very limited number of experiments 

 would likely be more misleading than in the plan we adopted. 



We summarize the following important points, deduced chiefly from our studies 

 of Crotalus venom, to which are added a few comments : — 



1. Venoms bear in some respects a strong resemblance to the saliva of other 

 vertebrates. 



2. The active principles of venom are contained in its liquid parts only. The 

 solid constituents, such as we observed suspended in the poison, consist of epithe- 

 lium cells, some minute rod-like animal organisms and micrococci, etc., which, 

 when separated from the liquid fresh venom by means of filtration and well washed 

 by water are harmless. Micrococci are constantly present in fresh venom, but have 

 nothing to do with its virulence. 



3. Venoms may be dried and preserved indefinitely in this condition with but 

 very slight impairment of their toxicity. In solution in glycerine they will also 

 probably keep for any length of time. 



4. There probably exist in all venoms representatives of two classes of proteids, 

 globulins and peptones, which constitute their toxic elements; the former may be 

 represented by one or more distinct principles. 



5. When venom is taken into the stomach in the intervals of digestion, enough 

 of the poison may be absorbed to produce death, especially in the case of those 

 venoms which contain a larger proportion of the more dialysable peptone ; but 

 during active digestion the venom undergoes alteration and is rendered harmless. 



6. Potassic permanganate, ferric chloride in the form of the liquor or tincture, 

 and tincture of iodine seem to be the most active and promising of the generally 

 available local antidotes. 



7. Venom exerts a powerful local effect upon the living tissues, and induces 

 more rapid necrotic changes than any known organic substance. It causes oedema, 

 swelling, attended with darkening of the parts by infiltration of incoagulable blood, 

 breaking down of the tissues, putrefaction, and sloughing. 



8. It renders the blood incoagulable. 



9. When brought in contact with a vascular tissue of a warm-blooded animal 

 it produces such a change in the capillary bloodvessels that their walls are unable 

 to resist the normal blood pressure, thus allowing the blood-corpuscles to escape 

 into the tissues. These lesions are, however, not analogous to those of inflamma- 

 tion, since in the latter process it is principally the white blood-corpuscles which 

 emigrate from the vessels, and the blood is highly coagulable, while here the blood 

 exudes en masse and coagulates with difficulty, if at all. Free access of air 

 (probably of oxygen) appears to lessen the virulent effects. The mesentery exposed 

 to air, and on which the venom is merely brushed, endures the venom longer and 

 in much larger quantity than when the poison is injected into the unopened and 



