Penetration of Marine Tissues by Alkali. 145 



HOLOTHURIA FLORIDANA (IMMATURE EGGs). 



N/80 NaOH — Eggs remain unchanged in size and appearance for 6 

 minutes; diameter 14.2 units. The surface layer then becomes clear, 

 the clear region extends inward, and in the course of 1.5 minutes more the 

 whole egg is clear and swollen to 16 units. The color change occurs as the 

 egg contents become clear. 



In N/ 1 60 and N/320 NaOH the color change occurs some time before the 

 egg clears and swells. Thus in N/160 NaOH the color change occurs in 18 

 minutes and cytolysis in 40 minutes. 



N/80 NH4OH — Color change is instantaneous. Eggs remain the same 

 in appearance and size for an hour; diameter 14.4 units. Then swell to 

 18 units in the course of 2 to 5 minutes. 



The immature eggs of Fissurella sp., Eurythoe sp., and an Amphitrite- 

 like worm behave as do those of the palolo. 



It was often noticed that if segmenting eggs were placed in NaOH differ- 

 ent blastomeres were entered at very different times by the alkali. Thus 

 the resistance of each individual blastom^ere is specific and on division the 

 daughter cells may become perfectly distinct from each other so far as 

 permeability relations go. Whether such differences are related to the 

 hereditary potencies of the individual blastomeres was not determined. 



It will be seen from the foregoing observations that several types of 

 eggs may be distinguished as regards penetration of NaOH and cytolysis, 

 viz: (i) Eggs in which cytolysis and color change are both simultaneous 

 and rapid {Toxopneustes and sea-urchin eggs in general) ; (2) eggs in 

 which cytolysis and color change are simultaneous but gradual {Eunice 

 and other annelids); (3) eggs in which color change may occur before 

 cytolysis {Holothuria floridana, immature eggs). 



In addition to the above: (4) eggs in which the color change occurs 

 after cytolysis {Cumingia, observed at Woods Hole, Massachusetts). 



In all types ammonia and the amines enter instantly, long before 

 cytolysis occurs. 



Only one egg thus far examined (that of Cumingia tellinoides) belongs 

 to type 4, and one egg only (that of Holothuria floridana) to type 3. In 

 other cases penetration of NaOH and swelling are simultaneous. 



Leaving aside for the moment the egg of Holothuria, which forms an 

 exception to the rule that cells are visibly affected before or at the moment 

 of entrance of NaOH, let us analyze the results obtained with eggs of types 

 I and 2. 



The rapid color change in ammonia shows how small the concentration 

 of OH ions need be to affect the red-stained granules. We may assume, 

 then, that if even a trace of NaOH entered the color change would be rapid. 

 Since practically all marine eggs remain quite unchanged in size and in color 

 (of the red-stained granules) in NaOH solution for some time and only 

 after a definite interval begin to swell and to change color relatively rapidly, 

 we may conclude that the NaOH can only force an entrance after funda- 



