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SCIENCE 



[N. S. Vol. XXVI. No. 666 



if, however, these media act through their 

 fat dissolving power, the reverse should 

 hold. Benzol is practically insoluble in 

 sea-water. For the purpose of the mem- 

 brane formation about 2 drops of benzol 

 were put into 50 c.c. of sea-water and the 

 mixture shaken. In order to increase the 

 solubility of the benzol in the sea-water the 

 latter was heated slightly. The shaking 

 caused an emulsion, but only a trace of the 

 few drops of benzol went into solution; 

 yet this caused the membrane formation 

 instantly in the eggs of the sea-urchin. On 

 the other hand, phenol is very soluble in 

 sea-water. It was necessary to add 6 c.c. 

 m./2 phenol (Kahlbaum) to 50 c.c. sea- 

 water to produce the membrane formation. 

 Moreover, although toluol has been used 

 extensively in experiments on protein solu- 

 tions, no author has ever noticed a coagu- 

 lating effect. Yet it is just as effective as 

 benzol for the production of the fertiliza- 

 tion membrane. I think there can be no 

 doubt that we are dealing with an action of 

 benzol, amylen, toluol, on the solution of 

 fatty compounds and not on coagulation. 



The second agency for the membrane 

 formation is a treatment of the eggs with 

 alkali. The saponifying action of alkalis 

 upon fat is too well known to require any 

 further discussion. 



The action of acids, however, is 

 very peculiar and interesting. As al- 

 ready stated, only such acids as con- 

 tain one (but not more) carboxyl group 

 produce the membrane formation in Stron- 

 gylocenlrotus purpuratus. HCl, HNO3, 

 H2SO4, NaH„ POj, and dibasic or tribasic 

 organic acids, e. g., oxalic, succinic, citric 

 acids, etc., were practically ineffective. 

 This shows that the effect of the fatty acids 

 can not be due to the hydrogen ion; the 

 hydrogen ion inhibits the process of mem- 

 brane formation, as can be shown by the 

 fact that the membrane can not be formed 

 as long as the egg is in the acidulated sea- 



water, but only after it has been trans- 

 ferred back to normal sea-water. More- 

 over, it can be shown that the ineffective- 

 ness of such acids as HCl, HNO3, etc., is 

 not due to a secondary injurious effect 

 upon the eggs, for an effective solution of 

 butyric acid remains just as effective if we 

 add to it the equivalent amount of hydro- 

 chloric acid. We are obviously dealing 

 here with a specific action of one group of 

 acids, namely, of those ivliich contain one 

 carboxyl group. Some of these acids, e. g., 

 acetic, are well-known fat solvents. Pflueg- 

 er pointed out long ago the fat-dissolving 

 action of oleic acid. All of these mono- 

 basic fatty acids are more soluble in fat 

 than the other acids. It is therefore pos- 

 sible that these acids act as fat solvents and 

 that it is due to this action that they cause 

 the membrane formation. 



But why should the membrane formation 

 in the egg be connected with the process 

 of fat solution? Several years ago I 

 showed that the process of membrane 

 formation in the egg is a transition stage in 

 such cases of cytolysis of the egg, whereby 

 the latter is transformed into a shadow. 

 If we treat eggs with benzol or amylen 

 they form a membrane and are a few 

 seconds later transformed into shadows. 

 The treatment of the unfertilized eggs with 

 alkali also transforms them rapidly into 

 shadows if the solvition is free from Ca or 

 Mg. In this process also a membrane is 

 formed. The treatment of the eggs with a 

 fatty acid does not cause cytolysis, but this 

 is due to the inhibiting action of the H 

 ions. Through the addition of acid to sea- 

 water the cytolytic action of fat solvents 

 like benzol is also inhibited. We can also 

 produce cytolysis by treating the eggs with 

 hypertonic sea-water of a very high osmotic 

 pressure, e. g., 1| to 2 m., or with very 

 dilute sea-water; in both cases the process 

 of membrane formation is a transitional 

 stage in the cytolysis. 



