OCTOBEB 4, 1907] 



SCIENCE 



435 



Experiments on cytolysis in red blood 

 corpuscles seem to show that the mechanism 

 of this process is the destruction of the 

 membrane of the red corpuscles chiefly by 

 lipolysis. Koeppe assumes (as is generally 

 agreed) that the surface of the red blood 

 corpuscle consists of a lipoid film which is 

 liquefied, saponified, or otherwise destroyed, 

 in cytolysis. I believe that the same is 

 true for the cytolysis of the egg, with this 

 difference only, that in the egg it is not the 

 most superficial film which is liquefied, but 

 the layer underneath it. The surface film 

 is preserved in this process; it is at first 

 quite thin and invisible, but very soon be- 

 comes visible, possibly through an imbibi- 

 tion with water which causes it to swell. 



The process of membrane formation, ac- 

 cording to these facts, seems to be due to a 

 solution of the fatty layer underneath the 

 surface film of the egg. This fatty layer 

 forms together with the surface film a 

 solid shell around the unfertilized egg. As 

 soon as the fatty layer under the surface 

 film is liquefied, water is squeezed out from 

 the cytoplasm and forms a layer between 

 this and the outside film which in the mean- 

 Avhile has become toughened. But how 

 could this process of fat solution and pos- 

 sibly lipolysis be connected with the syn- 

 thesis of nucleins 1 We can not answer this 

 question except by mentioning the possi- 

 bility, that the lecithins may be involved in 

 the liquefaction and hydrolysis of the sur- 

 face layer of the egg. 



The second question raised by us was: 

 Why does the process of nuclein synthesis 

 come to a standstill so soon after the 

 membrane formation (unless the egg is 

 treated with hypertonic sea-water) and 

 why does the egg disintegrate so rapidly in 

 this ease? To this question we are able 

 to give a pretty definite answer. We 

 stated in the beginning of this paper that 

 processes of oxidation are the conditio sine 



qua non of nuclein synthesis and develop- 

 ment in the fertilized egg. The nuclein 

 synthesis and the segmentation of the 

 nucleus and the cytoplasm after the arti- 

 ficial membrane formation also depend 

 upon oxidations and do not occur in the 

 absence of or the presence of KCN. It 

 can be shown that the disintegration . of 

 the eggs does not occur if the eggs are put 

 after the membrane formation into an 

 atmosphere of pure hydrogen, or if the 

 oxidations ai'e suppressed in the egg by the 

 addition of a trace of KCN. Eggs which 

 after the membrane formation are thus 

 treated remain intact and can be caused 

 to develop if after a number of hours they 

 are treated with hypertonic sea-water, 

 while at this time the eggs of the same ex- 

 periment which had remained in normal 

 sea-water are already disintegrating. We 

 must therefore conclude that the artificial 

 membrane formation causes or allows the 

 oxidations underlying the synthesis of the 

 nucleins, but that these oxidations do not 

 occur in the right direction ; and that these 

 faulty oxidations are the cause of the rapid 

 disintegrations of such eggs. This disin- 

 tegration occurs the sooner the higher the 

 temperature. 



This conception receives support through 

 the experiments intended to give an 

 answer to the third question, namely, how 

 it happens that eggs which after the arti- 

 ficial membrane formation are treated for 

 from 30 to 50 minutes with hypertonic sea- 

 water develop normally. It was found in 

 all experiments that a hypertonic solution 

 acts in this way only if it contains free 

 oxygen. If we substitute for the air pure 

 hydrogen or if we add to the hjq^ei-tonie 

 solution a small amount of KCN this effect 

 is not produced. If the eggs possessing 

 membranes are brought back from the 

 hypertonic solution free from oxygen or 

 containing KCN into normal sea-water, 

 they disintegrate in the same way as if 



