SECRETION AND COLLECTION OF VENOM IN SNAKES 151 



The total quantity of liquid venom that I found contained in 

 the two glands of the same reptile, when extirpated after death, 

 and after the snake had been in the laboratory for five months, 

 amounted to 1-136 gramme, which gave 0'480 gramme of dry 

 extract. 



We see, therefore, that the proportion of dry residue, including 

 albumin, salts, the debris of leucocytes, and the toxic substance, 

 oscillates between 20 and 38 per cent. Its strength varies with 

 the length of time that has elapsed since the snake's last bite or 

 last meal. 



From the histological standpoint, the process of the secretion 

 of venom, in the cells of the glands, may be divided into two 

 stages : — 



{a) A stage of nuclear elaboration. 



(6) A stage of cytoplasmic elaboration. 



These two stages are superposed and successive. 



In addition to the passive exchanges between the nucleus and 

 the cytoplasm, the nuclear mass actively participates in the secre- 

 tion. This participation is rendered evident : — 



(1) By the difference of chromaticity in the granules of 

 chromatin. 



(2) By the emission of formed granules into the cytoplasm, 

 granules which are spherical and of equal bulk, with the chromatic 

 reactions of differentiated intranuclear chromatin. 



(3) By the exosmosis of the dissolved nuclear substance, ac- 

 cessorily formed in an ergastoplasmic shape. 



These formations constitute, on the one hand, the granules 

 of veiiogen; on the other, the ergastoplasmic venogen. In the 

 poison-cell of Vipera aspis, and in the serous cell of the parotid 

 glands of Tropidonotus natrix (Grass Snake) the venogen is 

 elaborated chiefly in granular form. 



On entering the perinuclear cytoplasm, the granule of venogen 

 and the ergastoplasmic venogen may either disappear imme- 



