OCTOBEK 18, 1912] 



SCIENCE 



529 



lion. The eggs of Nereis when obtained are 

 in the stage of the germinal vesicle, whereas 

 those of Arhacia have formed both polar 

 bodies, and this is probably correlated with 

 the different rates of secretion of the agglu- 

 tinin. The agglutinin of Nereis is moreover 

 much more thermolabile, being destroyed at 

 ■95° 0. in ten minutes. In Nereis also it is 

 ■difficult to test other tissues satisfactorily, as 

 the animal is practically a bag of eggs when 

 sexually mature, but such tests as were made 

 indicate that the eggs alone secrete the agglu- 

 tinin. In other respects Nereis is a more 

 favorable form for study, as the sensitiveness 

 •of the spermatozoa is unsurpassed. 



III. As regards the important question of 

 specificity, it seems very probable a priori 

 that a substance which is produced only by 

 the eggs of a given species, and which is 

 agglutinative for the sperm of that species 

 should be specific. Now the egg-extract of 

 Nereis, which agglutinates Nereis sperm, is 

 entirely devoid of agglutinating effect on 

 Arhacia sperm, so that there appears to be 

 specificity of the Nereis agglutinin to this 

 ■extent at least. But the egg-extract of Ar- 

 hacia, on the other hand, is extremely toxic 

 and agglutinative for Nereis sperm, so that in 

 this ease either the agglutinin from Arhacia 

 eggs is not specific for its ovm sperm, or the 

 egg-extract contains, in addition to the spe- 

 cific agglutinin, another toxic substance. The 

 latter alternative is probable, as is shovTn by 

 the fact that the serum of the coelomic fluid 

 of Arhacia, which is not in the least toxic or 

 agglutinative for Arhacia sperm, is as strong 

 an agglutinative agent for Nereis sperm as 

 the egg-extract of Arhacia. The presence of 

 at least two sperm agglutinating substances in 

 Arhacia is therefore certain, viz., one in the 

 egg-extract, which is agglutinative for Ar- 

 hacia sperm, and one in the coelomic fluid not 

 agglutinative for Arhacia sperm but aggluti- 

 native for Nereis sperm. I assume, therefore, 

 provisionally, that both are present in the egg- 

 extract, and that the sperm iso-agglutinin of 

 Arhacia eggs is probably specific. 



This assumption is rendered more probable 

 by an observation made only once, and at the 



end of the season, so that its repetition this 

 year is impossible. I had preserved a strong 

 egg-extract of Arhacia for seventeen days. 

 This had been tested at various times with 

 Arhacia sperm and found to retain its ag- 

 glutinating power without any observable 

 diminution. But on the seventeenth day, 

 when the last Nereis of the season was 

 brought in, I was surprised to find that the 

 egg-extract in question had lost its aggluti- 

 nating power on the Nereis sperm. The 

 same sperm was agglutinable with an egg- 

 extract of Nereis eight days old; so that 

 the difficulty could not be with the sperm. 

 And the same egg-extract of Arhacia, on 

 retesting, was found to retain its aggluti- 

 nating power on the Arhacia sperm appar- 

 ently unaltered. The specific agglutinin is 

 therefore relatively stable with reference to 

 the conditions involved, and the non-specific 

 agglutinin or toxin is relatively labile. It 

 might, therefore, be possible to separate them 

 also by heat or other means. 



One of these would be to fix the non-specific 

 agglutinin of Arhacia egg-extract with Nereis 

 sperm, and test the filtrate for the persistence 

 of the assumed specific agglutinin with Ar- 

 hacia sperm. If the Arhacia agglutinin were 

 found to persist after the filtrate had lost its 

 Nereis agglutinating power, the presence of 

 the two agents in the egg-extract would be 

 demonstrated. Or if, after completely fixing 

 the specific agglutinin of Arhacia egg-extract 

 with Arhacia sperm, a Nereis agglutinating 

 agent were still found, the same conclusion 

 would be inevitable. Unfortunately, by the 

 time this stage of the analysis was reached, 

 the season for both forms was over, and this 

 experiment must be postponed for a year. 



IV. The egg-extracts contain not only an 

 agglutinin for the spermatozoa, but also an 

 aggregative agent, i. e., a substance towards 

 which the spermatozoa are positively chemo- 

 tactic. This may be readily demonstrated by 

 the form of the reaction when a drop of the 

 fluid to be tested is injected into a sperm sus- 

 pension beneath a raised cover glass. If an 

 aggregative agent be present, a ring of sper- 

 matozoa forms at or within the margin of the 



