284 E - E - J UST - 



the amount of sea-water used being taken into account is de- 

 termined by the length of the exposure to the butyric acid sea- 

 water: (i) Eggs which have been exposed for one minute or 

 more designated " over-exposed eggs " because they have re- 

 mained in the butyric acid mixture beyond the length of time for 

 best membranes cytolyze most rapidly; (2) eggs exposed under 

 the optimum time for perfect membranes which are designated 

 "under-exposed eggs" cytolyze more slowly; and (3) eggs which 

 have had the optimum exposure (around 35 seconds) for per- 

 fect membranes cytolyze at a rate which is intermediate of the 

 " over- " and " under-exposed " eggs. 



A. The Method. 



The procedure is as follows : Eggs shed into perfectly clean 

 dry watch glasses or dry eggs washed off the ovaries as they 

 exude or concentrated washed eggs are gathered up in a pipette. 

 A tenth or twelfth of these eggs is set aside as a control in 

 normal sea-water, the remainder exposed to 10 c.c. of butyric 

 acid sea-water. From the butyric acid sea-water after 10, 15, 20, 

 25, 30, 35, 40, 50, 60, 90 and 120 seconds equal portions of the 

 suspension are carried over to dishes containing 250 c.c. of sea- 

 water. The control eggs are then removed to a dish of 250 c.c. 

 of sea-water. Thus, a series of dishes containing approximately 

 equal masses of eggs is made. Citations from the observations 

 follow. 



B. The Observations. 



The following protocols, the first of the thirty 1919 observa- 

 tions and confirmatory of others previously made, are in no 

 wise selected. They are given because they are simpler to pre- 

 sent than some of the later which are bound up with other ex- 

 periments of a different category the presentation of which 

 might draw attention from the salient feature which is under 

 consideration. 



Experiment 2 B. June 14, 8:00 A.M. Eggs taken from a 

 very good female as they exude from the ovaries. Control in 

 sea-water, remainder placed in 10 c.c. butyric acid sea-water 

 from which portions removed to 250 c.c. of clean sea-water at 

 intervals of 10, 15, 20, 25, 30, 35, 40, 50, 60, 90, and 120 seconds. 



