CHROMOSOMES AND SEX-DETERMINATION 407 



I. Ehrlich's Triacid Stain. 



Sections were immersed for eighteen hours in the stain, 

 blotted, and passed through absohite alcohol and xylol into 

 balsam. The chromosomes and the elimination plate were 

 stained purple, the surrounding protoplasm brown. 



II. Safranin and Lightgreen. 



Sections were placed in safranin for from twelve to twenty- 

 four hours, followed by lightgreen for one to two minutes. 

 The chromosomes were stained a bright red, the elimination 

 plate a lighter red in some cases and in others green with 

 a distinct admixture of red. The spindle-fibres were green. 



Both the above methods gave very clear results which strongly 

 suggest that chromatin was present in the elimination plate. 



III. Mann's Methyl Blue Eosin. 



Sections were stained for a few minutes only. This method 

 gave very erratic results. In most cases the spindle-fibres 

 were blue, but whereas in some sections the chromosomes 

 and elimination plate were also blue, in others the chromosomes 

 were purple and the elimination plate red ; and in others again 

 the chromosomes were red with a bluish tint here and there, 

 and the elimination plate purple. 



In spite of the varying results obtained with this stain it 

 is clear that in any given section there is a very close corre- 

 spondence between the chromosomes and the elimination plate. 



IV. Ehrlich's Haematoxylin. 



Sections were stained for eighteen hours with Ehrlich's 

 haematoxylin, differentiated for from one to two minutes in 

 acid alcohol, washed in 70 per cent, alcohol and counterstained 

 with eosin in 90 per cent, alcohol for about one minute. The 

 spindle-fibres always stained pink, the chromosomes were 

 usually black, and the elimination plate pink with grey dots ; 

 sometimes, however, the chromosomes were a bright pink and 

 the elimination plate a paler pink, and at other times the 

 chromosomes and the elimination plate were purple. 



Here again, as with Mann's methyl blue eosin, the chromo- 



