2 74 CALKINS. [Vol. XI. 



needles, for the groups of spermatic cells are not attached to 

 the trabeculae of the vesicles. After an exposure of not more 

 than ten minutes in Hermann's fluid the acid is drawn off and 

 the cells washed many times with distilled water, allowing 

 them to settle each time. The cells are then passed succes- 

 sively through fifty, seventy, and ninety per cent, and are 

 finally brought into absolute, alcohol. With a fine pipette they 

 are then transferred to a slide coated with equal parts of ^^^ 

 albumen and glycerine. The alcohol evaporates rapidly, leaving 

 the cells firmly attached to the glass by the fixing substance. 

 The only care necessary is to prevent actual drying of the 

 specimens. After this treatment slides can be handled roughly 

 in the alcohols and stains without detaching the cells. This 

 method offers great advantages over the preceding, and gives, 

 I think, truer pictures. Any stain may be used with these 

 preparations. For archoplasm masses Kleinenberg's haema- 

 toxylin gives the best result, but curiously enough this stain 

 does not affect the archoplasm in sections prepared either by 

 the paraffine or celloidin method. Chromosomes are most 

 clearly defined by the use of Flemming's triple stain, while the 

 best differentiation of the cytoplasmic and nuclear elements is 

 obtained by the combined use of iron haematoxylin and orange. 

 Good results are also obtained by fixation with corrosive 

 sublimate, and with chromic and picric acid solutions. These 

 acids, although unquestionably distorting the cells, distribute 

 the nuclear elements to a certain extent and render them more 

 conspicuous. Their peculiar effect on the archoplasm will be. 

 described later. 



II. The Blastophore, 



The blastophore, considered by Bloomfield ('80, '8i) as equiva- 

 lent to the vertebrate Sertoli cell, is thus briefly described in 

 his paper : " It is in this stage (late spermatogonium) that 

 there is first any indication that as the spermatoblasts are 

 being formed, a slight quantity of protoplasm is being left be- 

 hind in the center of the generating polyplast, which, as 

 development proceeds, will form the cushion on which the 

 sperm rods may rest. It is best seen in polyplasts which have 



