NOTE ON THE PIGMENT OF ARBACIA 

 EGG-SECRETION. 



OTTO GLASER. 

 I. 



If the unfertilized eggs of Arbacia punctulata are allowed to 

 secrete into a small volume of sea-water, the latter, in the course 

 of five or ten minutes, takes on an amber color. The density of 

 the pigment varies with the concentration of the eggs as well as 

 with the time during which they secrete. After an hour, the 

 sea- water is apt to become reddish-brown. 



The later discoloration is due, at least in part, to the elimination 

 of echinochrome a substance which these eggs contain in con- 

 siderable quantity. Whether the pigment given off during the 

 earlier moments of secretion is also echinochrome remains 

 uncertain since the diagnostic reactions recommended by Mac- 

 Munn ('85) are not convincing at the dilutions at which it is 

 necessary to work. In exudate of more than "standard" 

 strength I have been unable to see that HC1 produces a red tint 

 or that NaOH intensifies the yellow. With precipitated pigment 

 both acid and alkali seem to intensify the yellow color to an 

 extent barely perceptible. 



II. 



One cannot assume, offhand, that the pigment is either impor- 

 tant or negligible in fertilization. In my study of egg-exudate, 

 therefore, I first attempted to decolorize the secretion in order 

 that the lipolysin and agglutinin subsequently recovered by other 

 methods might be either free or relatively free from pigment. 

 For this purpose charcoal cannot be used since it has the serious 

 disadvantage of removing the whole, practically, of the organic 

 reaction system. Moreover, the pigment, if wanted for separate 

 study, cannot be recovered readily from the charcoal. 



To isolate the pigment, it is much better to use chloroform as a 

 decolorant. The method is very simple. To a given volume of 



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