276 Transactions of the Society. 



50 p.c, 30 p.c. alcohol, an hour or so in each grade, and place direct 

 into carmalum for twelve, twenty-four, thirty-six hours, according 

 to the size of the objects. Remove and wash in distilled water 

 until no more colour comes away; graduate back to absolute alcohol, 

 ■clear with cedar-oil and embed in paraffin. Cut sections, which 

 should not be over 10/i, and iix, by the water method, to the cover- 

 glass ; remove paraffin-wax by cedar-oil, wash away the oil by 

 absolute alcohol, and, subsequently, in one or two changes of 

 methylated spirit. Counter-stain, by immersion for a quarter of an 

 hour, in a solution of Gruebler's light green in methylated spirit. 



Light green . .0-5 grms. 

 Methylated spirit . 200 c.cm. 



Wash out in one or two changes of methylated spirit, then 

 absolute alcohol, cedar-wood oil, xylol, and, finally, mount in 

 euparal, not balsam or other media. 



One of the distinguishing features of this method is that the 

 cytoplasm of dividing cells, or cells about to enter upon mitosis, 

 is stained a deeper green tone than those not dividing. All nuclei 

 and nuclear material are sharply contrasted from cytoplasm, not 

 by grades of intermixed red and green, but by a complete distinc- 

 tion between the two colours. When differences are to be seen it 

 is only to be observed in varying depths of one or the other stain. 



Finally, on comparing a mounted section which has not been 

 counter-stained with light green with another that has, it will be 

 observed that the counter-staining has the effect of considerably 

 intensifying the carmalum stain, and at the same time rendering 

 it sharper and crisper in detail. 



2. The second method is one which has been formulated for 

 staining tissues in bulk with an iron preparation of hajmatoxylin. 

 The formula for the preparation of the stain was given in the 

 Journal, Clinical Eesearch, May 1910, page 63 ; a short time after 

 it appeared, by permission, in the Journal of Micrology. I have 

 given this stain an extensive trial and am convinced of its value. 



Fix and harden as already described. Place the pieces in a 

 freshly-made mixture of the two following solutions : — 



1. HEematoxylin . . . . . .1 grm. 



95 p.c, alcohol ...... 100 c.cm. 



2. Perchloride iron . . . . . 2 ,, 

 Hydrochloric acid . . . . . 1 „ 

 4 p.c. aqueous solution copper acetate . . 1 „ 

 Water 95 „ 



Transfer the material to the stain, and allow to remain for a 

 somewhat longer period, say half as long again, than would be the 

 case when carmalum is employed, for the reason that this stain is 

 not so penetrating. Should the piece of tissue be large — that is, 



