372 BOTANICAL GAZETTE [MAY 
eggs of Chaetopterus could be made to divide by placing them 
in sea water to which KCl had been added. Morgan™ con- 
firmed the results obtained. by Hertwig as to the action of 
strychnin sulfate. He expressed the opinion that eggs are ina 
state of unstable equilibrium, and-would react to various stimuli 
by division just as other cells would react in other ways to the 
same stimuli. Loeb*s found that exposure of eggs of Arbacia 
for a short period to sea water to which alkali or acid had been 
added induced cell division. He has arrived at certain com 
clusions by further experiments upon the unfertilized eggs of 
-echinoderms.** He has shown that such eggs can be made to 
develop into normal embryonic forms through a certain increase 
in the osmotic pressure, produced either by electrolytes or non” 
electrolytes. He suggests the probability that parthenogenetic 
_ development is caused by loss of a certain amount of water 
the egg. Mathews’? found that karyokinetic divisions in the eg 
ee of Arbacia could be induced by the lack of oxygen, by heat, by 
exposure to ether, alcohol, and chloroform. Loeb” also 
duced artificial parthenogenesis in eggs of other animals | 
: echinoderms by increasing the osmotic pressure, as Chae 
te His experiments have convinced him that the . 
fea re in increasing the osmotic pressure of ae surre 
| = te 
if we assume the spermatozoon starts the 
he egg in the same way as in the case of artificial pé 
esis, must follow that it possesses more salts 
our tage than the egg. He has also sugges est! 
we. 
in Tiahictam. “The egg is is inve t 
‘plasm, and that = is som = re 
