308 MYRA MKLISSA SAMPSOX. 



Experiments in which blood plasma was passed through a 

 Berkefeld filter, Cramer and Pringle (1913), and Goddard (1914), 

 demonstrated that the filter held back for a time, not only 

 suspended elements, but the various proteins in colloidal solution, 

 but the third portion passed through the filter contained some 

 fibrinogen. Mudd (1922) suggested that in alkaline solution 

 protein may be carried through in small amounts. The filter 

 itself is negatively charged and because of the amphoteric 

 properties of protein the latter dissociates as an anion in alkaline 

 solutions and so would tend to be carried through the filter. 



It is important therefore to determine if possible whether 

 nitrogen compounds are present since Loeb (1914) states that 

 protamine will induce the first cell divisions in eggs of Arbacia; 

 and Labbe (1923) using a one to forty thousand solution of 

 sodium nucleinate in sea-water on unfertilized eggs of Arbacia 

 obtained some swimming larvae. Because of buffer action these 

 solutions had the same hydrogen-ion concentration as sea-water, 

 and Labbe concluded that the sodium nucleinate exerted a 

 specific action not due to its hydrogen-ion concentration. 



All the usual tests for protein or protein split products such as 

 guanine, protamine, and nucleic acid were negative. A micro- 

 kjehldahl test, performed for me by Dr. \V. Dennis, was also 

 negative, indicating that nitrogen is not present in sufficient 

 amounts to be detected by this method. Incineration tests gave 

 evidence of the presence of carbon in larger amounts in both 

 filtrates and dialyzates than in sea-water. 



b. Physiological Properties. From the presence of carbon in 

 these preparations it is certain that they contain something of 

 organic origin. It seemed possible that they might produce 

 changes in the ova of foreign species, since sperm extracts ob- 

 tained by other investigators have produced marked effects on 

 ova of foreign species even when they had no influence on ova 

 of the same species, Loeb (1916, p. 102). Consequently tests 

 were made to determine whether Arbacia sperm filtrates would 

 affect the ova of Nereis limbata, a form in which maturation 

 follows insemination. Seventeen experiments were performed in 

 which ten preparations were used on Nereis eggs. The results 

 obtained resemble in many respects those produced by in- 



