ORIGINAL Mrvuop or ARTIFICIAL PARTHENOGENESIS 161 
put directly into hypertonic sea-water (50 c.c. sea-water+ 
8 c.c. 2} .m NaCl). Temperature 18° C. 
The maximum consumption of oxygen was reached in the 
second hour in which the effect of membrane formation was 
almost complete. In this case the eggs of a female were used 
TABLE XXXI 
UNFERTILIZED Eaes 
Oxygen | Coefficient of 
Consumed Rate of Oxidation 
WNormealsea-water: .... Sa...) -.....d.6% | 0.16 mg. 1.0 
Hypertonic sea-water; ist hour........ 0.67 4.2 
Dilhourses 2. | 0.79 4.9 
SUehOULse eee 0.64 4.0 
4thehour: 223-2 | 0.56 3.6 
Sth hour. 2. «2-6 | 0.57 3.2 
which were obviously very susceptible to this treatment. The 
effect of the hypertonic solution upon the rate of oxidation in 
the unfertilized egg was as great as that produced by artificial 
membrane formation through butyric acid or by fertilization 
with sperm. 
In many cases the treatment of eggs of S. purpuratus with 
hypertonic sea-water leads to no membrane formation and no 
development, or only to the development of a limited number 
of eggs. Consequently the rise in the rate of oxidation caused 
in such cases should be smaller than that caused by artificial 
membrane formation with butyric acid which usually takes 
effect in practically all the eggs. 
We give in Table XXXII a series of experiments with 
hypertonic sea-water of various concentrations. It should be 
remembered that the addition of 4 c.c., or less, 2 m Ringer to 
50 ¢.c. of sea-water was without effect. The oxygen consump- 
tion was first measured in normal sea-water, then, for the same 
quantities of eggs, in a hypertonic solution. The table gives 
the ratio of the oxygen consumption in hypertonic to that 
in normal sea-water. 
