1893.] Embryology. 399 
The behavior of the nuclei of the eggs in concentrated sea water 
was observed somewhat in live eggs and in certain stained eggs which 
Dr. Conklin prepared for the author. It seems that the nuclei increase 
in numbers in the salted sea water when there are no cleavage furrows 
visible on the outside of the egg, but this increase is not alwàys accom- 
panied by a normal separation. 
In the light of the conceptions of Fol and O. and R. Hertwig 
regarding the effects of polyspermy in producing a cleavage into many 
simultaneously formed cells it might have been urged that Dr. Loeb’s 
results were due to polyspermy. 
Granting, however, that the increase in nuclei takes place while the 
eggs are in the salted sea water such facts as the effect of this water in 
paralyzing the spermatozoa, as observed by the author, show that the 
spermatozoa cannot be connected with these peculiar cleavage phe- 
nomena. i 
Regarding the method of action of the salt used in these experi- 
ments we must premise that the author in previous work upon hydroids 
came to the conclusion that growth and regeneration in animals and 
plants is a function of the amount of water contained in the cells. 
The application of this to the present case is in the idea that increas- 
ing the concentration of the liquid about a cell decreases its irritabil- 
ity by removing water from it ; the effect is the same quantitatively 
and qualitatively as would be produced by lowering the temperature. 
- The normal source of the stimulus which the abstraction of water 
is supposed tọ render no longer efficient to produce cleavage is con- 
sidered to be the nucleus. The nature of this stimulus is unknown, 
but some facts lead toward the sumption that it may be a chemical 
one 
On the other hand the protoplasm has some influence upon the 
nucleus ; possibly the intracellular pressure determining the form of 
the cell also fixes the direction of the nucleus, which will then be less 
defined in a mass without cell walls. 
