NEUROTOXINS OF SNAKE VENOM 155 
diffuse staining begin to disappear and leave a skeleton cell, with its margin, 
the reticulum, and nucleus being somewhat deeply stained but very well 
differentiated. The staining later becomes gradually less intense until we 
reach the stage in which the cell is little more then a shadow of its former 
self —the typical ‘‘ghost” cell. Vacuoles next appear in the body of the 
cell and its margin becomes indented as if little pieces had been snipped out. 
Then portions of the cell disappear altogether and leave little more than a 
nucleus with the remains of the cell reticulum attached to it. All this time 
the nucleus, at least in a large proportion of the cells, seems to be little affected 
otherwise than is shown by a varying intensity of its staining. It remains 
central, is only exceptionally found at the periphery of the cell, and though 
it is sometimes lost to view in the diffuse staining of the earlier stages it is 
almost always to be seen in the later stages of degeneration. Vacuolation is 
most seen in the pale (ghost-cell) stage, but it is also to be met with in the more 
deeply stained cells. The connective tissue elements of the gray matter 
seem to play a somewhat secondary part in this degenerative process. They 
may be slightly increased in number around the ganglion cell in its earlier 
stages of chromatolysis, but this increase is not considerable and it is not till 
vacuolation comes on and the cell begins to break up that they are seen to 
cluster definitely around the disappearing cell. During this later stage, and 
sometimes at an earlier stage, they are found indenting the margins and are 
sometimes inside the body of the cell. 
The chromatolytic changes just described appear to be uniformly most 
advanced in the smaller cortical cells and in the cells of the more central 
group in the anterior horns of the cord. The larger cortical cells and certain 
of the cells in the lateral groups of the anterior horns seem to be considerably 
more resistant to the toxin, for they are slower in showing degeneration, and 
when it does appear it is hardly ever so extreme as in those other cells. Of 
the motor nuclei in the pons and medulla the ganglion cells of the third and 
fifth nuclei were usually affected about equally with those of the cortex and 
cord. But the seventh, tenth, and twelfth nuclei showed changes less often 
at a later period, and of a less intensity, than any of the other motor cells in 
any part of the central nervous system. 
In addition to the above description they found that the venom of Enhy- 
drina valakadien, when allowed to act for several hours, produces granular 
disintegration of myelin and fragmentation of axis-cylinder, thus showing its 
widespread action on the whole nervous system, not only on ganglion cells, 
but also on nerve fibers. 
