6 THE VENOMS OF CERTAIN THANATOPHIDE^E. 



after point out. 1 Neither does it appear to be injured when dry by mingling it 

 with pure alcohol. In fact any of these three means, desiccation, glycerin, or 

 alcohol, preserves it well. 



When fresh venom of any serpent is examined with the microscope it often 

 presents a variety of floating bodies which seem to be much alike in all cases, and 

 are very well shown in the plates of Dr. Mitchell's former paper and in Vincent 

 Richards's reports. In healthy serpents, but lately caged, there are fewest of 

 these solid ingredients, as has been noticed by Richards, by Wall, and by S. Weir 

 Mitchell. The question of the toxicity of these suspended solids has again drawn 

 our attention to them, and we have had yet more careful and repeated microscopic 

 examinations made by Prof. Formad. He found, like other observers, that the 

 venom of the more vigorous snakes has the least visible solid matter ; but, as in the 

 use of the fang, the mucus and floating solids of the mouth must be considered, 

 and, as in collecting venom from the snake, more or less of the mouth fluids mingle 

 with the venom, it was thought well to reconsider the nature of the floating solids 

 from the point of view of toxic activity. For the better study of the solids found 

 in venoms we examined numerous specimens, and placed many of these in the 

 hands of Prof. Formad, from whose notes we select the following observations : 



A drop of fresh venom, taken directly from the Crotalus adamanteus, was examined 

 with a T V Zeiss. homog. immersion lens ; amplification 800 diameters. The most 

 striking appearance which first meets the eye is a granular material scattered about 

 in masses of various size and shapes, resembling those formed by bacteria. There 

 are also seen, in some cases, a few oval nucleated red blood-corpuscles, some leuco- 

 cytes resembling salivary corpuscles, and others corresponding to ordinary white 

 blood-corpuscles, the latter cells in an active state of amoeboid motion. There 

 were also observed several club-shaped epithelial cells covered with fine granular 

 material. 



The granular matter first mentioned, and which seems to form the main solid 

 constituent of the venom, consists of two elements: Larger granules of an animal 

 or albuminous character, and a fine granular material of vegetable nature. The 

 albuminoid material is made up of minute particles ovoid, or somewhat irregularly 

 angular in shape, measuring about T7 ^^ of an inch in their longest diameters. 

 These ovoid particles are grouped side by side, from two to twenty in each collec- 

 tion, and are arranged so as to form single or double rows, or more often aggregated 

 into irregularly shaped clusters, which vary in size from -gfa to -g^rnr f an nic h ; 

 the smaller masses predominating. The particles just described are colorless, 

 refracting, and in general give the impression of bacteria. They are, however, 

 distinguished from the latter in that they do not multiply in cultures, or respond 

 to the aniline dye test for bacteria. 



There are usually numerous bacteria in perfectly fresh venom. All the smaller 

 particles and granular material are micrococci, measuring on an average T7 | 7Tr of 

 an inch in diameter, are perfectly round or somewhat ovoid, and occurring singly, 



1 Dr. Mitchell possessed a glycerin solution which was toxic after twenty years. 



