1395.] Embryology. 385 
EMBRYOLOGY.’ 
EPE ann: EROI W Hoem Roux, the leader of the new 
school of Embry th al phenomena 
by the aid of scperinental methods, has: published. j in ka new period- 
ical some very interesting results obtained on his-often used object, the 
frog’s egg.” 
The eggs were teased apart in salt solution, white of egg, or in a 
mixture of both, and observed under precautions necessary to prevent 
currents and jars in the liquids. When so treated the isolated cells, 
for eggs are used in later cleavage and bastula stages when each is 
divided up into many cells, lie in the liquid at varying distances from 
one another and quite separate. 
It is now found that movements may take place that results in the 
union of some of these isolated cells. These movements are a gliding 
or creeping, since the cells lie on the glass slide and not suspended in 
the liquid. In many cases, especially when salt solution is used, the 
cells throw out pseudopodia that may be all clear protoplasm or else 
contain a granular axial mass. These may anastomose with pseudo- 
podia of other cells. The pseudopodia, however, are not concerned in 
the motions which are actual translations of entire cells without any 
visible means or cause. : 
The movements do not take place between all cells and seem to vary 
in power in the same cells. In the frog Rana fusca eggs from the latter 
part of the breeding season show no movements. In other species 
namely R. esculenta, Bombinator igneus and in the fish Telestes agassizii 
no movement could be detected. 
In detail these movements are found to be of limited extent but yet 
capable of resolution into considerable complexity. Only cells having 
diameters of from 20 to 60 microns show the phenomena and only when 
not more than their own diameter apart. Weare thus dealing with mi- 
gration of small amounts of matter along very short distances. The cells 
move along the shortest distance between them but not without vibra- 
tions from side to side. The latter part of their course when about to 
unite is generally more rapidly accomplished than the first. A few 
minutes to an hour or two may be taken in moving these short dis- 
tances, e. g. 40 microns. 
'Eaitea vy E. A. SRR Baltimore, Md., to whom abstracts, reviews and 
pona notes ma 
2? Archiv f. PLT PE Vol. I. Oct. and Dec., 1894. 
