CYTOLYSINS IN SNAKE VENOM 203 
TABLE 15.— Continued. 
[Experiment III: Lepidonatus squamatus (Scale-worm).] 
Time of 18 2 per cent moccasin 2 per cent crotalus 
= in water. I nt cobra m. 
at en. Control in sea per ce veno cared. 
Large, transpar- | Very marked agglutina- | Like cobra. Moderate aggluti- 
ent cells with tion; membrane intact; nation; no other 
distinct mem- vesicle granular; nuclei change. 
brane; germi- distinct. 
nal vesicle, etc. 
No change. Little change. Little change. Moderate aggluti- 
nation; no other 
change. 
No change. Cell membranes unrup- | Little change. Germinal vesicles 
tured; germinal vesicles granular; no 
fragmented. other change. 

[Experiment IV: Fundulus heteroclitus (Minnow).] 
30 mins. Greenish - blue- | Pigment quickly dis- | Similar to cobra | Unchanged. 
opaque cells solved; germinal vesicle venom. 
with irregular much swollen or frag- 
contours; ger- mented. 
minal vesicle 
covered with 
pigment and 
obscured. 
No change. Many cells have ruptured | Similar to cobra | Swelling of cells. 
and emptied contents. venom. 
No change. All membranes emptied. Few membranes | Partial disintegra- 
with contents. tion. 

Flexner and Noguchi next determined the action of venom upon the fer- 
tilized ova of Fundulus, Arbacia, and Asteria. Observations upon these cells 
were conducted under two sets of conditions: (a) fertilization was attempted in 
venom solutions, and (b) venom in solution was added to the fertilized eggs 
at different periods of segmentation. The following facts appeared: 
Fundulus ova: 
(1) Venom in strong®solution (5“per cent cobra) dissolves the-fertilized ova, 
but in weaker solution only delays segmentation. 
(2) After fertilization and beginning segmentation weak solutions of venom 
do not prevent further segmentation. 
(3) Brief treatment with weak venom solutions of the segmenting ova up to 
the time of the morula stage causes only delayed development. 
(4) Brief treatment of the embryos with weak solutions at about the period 
of formation of the brain and optic vesicles (36 hours) causes malforma- 
tion and delays the hatching. 
(5) More advanced embryos are more resistant, but finally may succumb 
to venom poisoning. 
Arbacia and Asteria ova: 
(z) Strong solutions (5 per cent cobra) of venom prevent fertilization, but 
weak solutions permit its occurrence. 
(2) Strong solutions of venom delay segmentation, while weak solutions 
cause imperfect and irregular segmentation. 
(3) Brief treatment with weak venom solution accelerates the blastula forma- 
tion, while the plutei are killed by strong solutions of venom. 
