166 ARTIFICIAL PARTHENOGENESIS AND FERTILIZATION 
alone is not able to induce the (stunted) membrane formation 
in the eggs, but the addition of alkali increases the membrane- 
forming power. This can be proved by the fact that the ad- 
dition of alkali to the hypertonic solution causes a rise in the 
rate of the oxidations of almost the same order as the addition 
of the same amount of base to an isotonic solution (Table 
XX): 
TABLE XXXIV 
Number of | ,- a ‘ : Oxy Coefficient 
Hy perinient | Unfertilized Eggs (without Membranes) in Céannaee of Rate of 
Oxidations 
mgn. | 
I INormalesea=watersacstarete ee 0.22 1.00 
50 ¢.c. hypertonic sea-water+1 c.c. 
ING/OSIN EN, © Ears, Greece ee ees 1.20 5.40 
50 ¢.c. normal sea-water-+1 e¢.c. N/10 
Ns BAO) b Chama eee errr ede cians acre eG ; 0.88 4.00 
Il Normal: sea-waterss, 45. sno nee fae ONG 1.00 
50 c.c. hypertonic sea-water+1  c.c.| 
N/10°benzylamine eee ee 1.89 5.10 
50 ¢.c. normal sea-water +1 ¢.c. N/10 
benzylamine’, ss.-.<)eaeie cree eee es sdb ied: 4.70 
{il Normal sea-water. 1s... sees eee) 0.36 1.00 
50 c.c. hypertonic sea-water+1 c.c. 
| “N/10 butylamime! =. 323-268 Bais 4.80 
| 50 c.c. normal sea-water+1 c.c. N, 10) | 
lbutylamiine sae ies eictecs ester te eee | el O- | S460 
It is obvious that the weak base alone raises the rate of 
oxidations practically to the same height as the combination 
of base and hypertonic sea-water. The whole rise was due in 
both cases to the membrane-forming effect for which the weak 
base was sufficient. 
In the case of a strong base, the result may be different, 
since in purpuratus neither the base nor the hypertonic solu- 
tion alone may cause membrane formation (or the change in 
the cortical layer of the egg) necessary for development. The 
following may serve as an example (Table XXXV). Duration 
of experiment one and one-half hours; temperature 18° C. 
: ye 
