LEWIS V. HEILBRUNN. 



but he still clings to the view that the swelling of a colloid is 

 involved. This is the identical view earlier expressed by Fol, 

 Herbst, etc. Because of the similarity between membrane eleva- 

 tion and haemolysis, Loeb introduces the term lysine to denote 

 any substance of unknown chemical composition which will 

 produce membrane elevation and cytolysis. It is evident that 

 the sperm may contain a lysine. 



R. S. Lillie 1 suggests a possible cause of swelling. He assumes 

 that at fertilization the outer surface layer of the egg becomes 

 more permeable to the salts of sea-water. These can now exert 

 no osmotic pressure against it, but since this outer fi'm or mem- 

 brane must still remain impermeable to the colloids within, 

 these do exert osmotic pressure, 2 and an inflow of water with 

 consequent swelling of some of the peripheral cytoplasm occurs. 

 The cause of such an increase in permeability has only been 

 hinted at. Its actual occurrence Lillie bases on the evidence of 

 McClendon, Lyon and Shackell, and Harvey. But even granted 

 such a chang of permeability, might it not just as wel be re- 

 garded as a result rather than as a cause of membrane elevation? 

 Harvey's 4 view is very much the same. He agrees with Loeb 

 that the membrane elevation is due to the swelling of a colloid, 

 and at the same time brings evidence in favor of Lillie's hypothe- 

 sis of increased permeability of plasma membrane. But Harvey 

 also believes that the presence of the "membrane substance" is 



1 R. S. Lillie, Amer. Journ. Physiol., XXVII., 301 (1911). 



2 Lillie considers osmotic pressure and "Quellungsdruck" synonymous, but this 

 is obviously improper, for the osmotic pressure of colloids is almost negligible, the 

 " Quellungsdruck," on the other hand, may exert a pressure of over 40 atmospheres. 



3 J. F. McClendon, Amer. Journ. Physiol., XXVII., 240 (1910); Lyon and 

 Shackell, Science, N. S., XXXII., 249 (1910); Harvey, Science, N. S., XXXII. , 

 565 (1910). The first two papers do not prove increased permeability of the 

 membrane. They only show that fertilized eggs stain more readily than those not 

 fertilized, a phenomenon which may also depend upon an increased rate of ad- 

 sorption after fertilization, or to a lowering of osmotic pressure, such as Bach- 

 mann (Arch. f. d. ges. Physiol., CXLVIIL, 141 (1912)) concludes for the egg of 

 Triton. McClendon's results are also unsatisfactory. He observed an increased 

 conductivity after fertilization, and from this concluded an increased permeability 

 of the outer layer or membrane. Such an increase in conductivity may well have 

 been caused by a disintegration of some of the eggs. The action of the electric 

 current, or the centrifuging which preceded conductivity determinations, might 

 readily produce disintegration. 



4 E. N. Harvey, Journ. Exp. Zoo/., VIII., 355 (1910). 



