PIGMENT IN ARBACIA EGG-SECRETION. 257 



fresh exudate, one adds, roughly, half a volume of chloroform and 

 shakes vigorously for fifteen minutes. In this time an emulsion 

 is formed in which the individual globules are remarkably stable. 

 The system, indeed, is a jelly, white in appearance and surpris- 

 ingly voluminous. In fact, both its volume and stability at first 

 misled me into thinking that I had found a method for precipitat- 

 ing, if not all, at least the greater part of the organic solutes 



present. 



III. 



On standing, the jelly separates from both the unemulsified 

 chloroform and the remainder of the exudate. 



The degree to which the latter is decolorized varies, among 

 other things, with its age. If the exudate is perfectly fresh, the 

 pigment is removed almost if not quite completely; if the secre- 

 tion is 36 or more hours old, decolorization is more difficult and 

 the chloroform jelly less stable. 



Microscopic examination of the jelly reveals on the surface of 

 each chloroform globule a delicate skin, translucent, with pearly 

 sheen, continuous, yet also with suggestions of extremely fine 

 fibrils. As the chloroform evaporates, this skin wrinkles until fi- 

 nally there remains an empty bag. 



Since the original exudate contained sea-salts, I washed the 

 jelly on a filter or shook it for half an hour in several changes, 

 first of fresh, and later of distilled, water. Under this treatment 

 the globules of chloroform break up into still smaller spheres 

 greatly increasing the stability of the system. The jelly can be 

 freed from sea-salts entirely and in this state has been kept for 

 weeks in stoppered bottles. 



IV. 



The material in the walls of the globules can be recovered 

 simply by permitting the chlorofrom to evaporate. Slight heat 

 naturally facilitates the process. The jelly, also, may be broken 

 down instantaneously by means of 95 per cent, alcohol. The 

 vesicles are permeable for the alchohol and this, itself, is soluble in 

 chloroform. Since the material held in the walls of the globules 

 is insoluble in both alcohol and chloroform, precipitation is 

 inevitable. 



