CHAPTER XXXVI. 543 



point of a needle and caused to touch the surface of the alcohol 

 immediately above the small objects. The dense albumen solution 

 falls at once through the alcohol and spreads out over the objects 

 on the liver ; at the same time the glycerine is extracted and the 

 albumen coagulated by the alcohol, with the result that the objects 

 are stuck on to the liver. The liver is now trimmed with a scalpel 

 into a rectangular shape and embedded in the usual way. 



Minchin used this method for the stomachs of fleas. I have found 

 it most successful for Echinoderm and other small eggs. 



Or the f ollowing method may be used :- -The organisms should be 

 strongly fixed, then dehydrated and cleared, and brought into 

 melted paraffin in a small watch glass. After a few minutes therein 

 they are brought on a cataract needle on to a small block of paraffin, 

 and arranged there with a heated needle and sectioned. They may 

 be stained after fixation, or the sections may be stained on the slide, 

 186 or 187. 



ENTZ (Arch. Protistenk., xv, 1909, p. 98) brings the objects from 

 clove oil into clove oil collodion of the consistency of honey, then 

 brings them in this into a funnel made of paraffin, and when they 

 have collected at the bottom of this puts it into chloroform, which 

 dissolves the paraffin and hardens the collodion. 



Some Current Stains for Protozoa. Below are given a number of 

 special staining methods suitable for routine protozoological work. 



1023. HEIDENHAIN'S Alcoholic Iron Hsematoxylin. (1) Fix in 

 Schaudinn's solution for fifteen minutes. 



(2) Place at once in 70 per cent, alcohol for at least one hour. 



(3) Mordant for five hours or more in 



50 per cent, alcohol . . . . .10 parts. 

 4 per cent, aqueous iron alum solution . 1 part. 



(4) Stain for twelve to twenty-four hours in 



Heidenhain's hsematoxylin ... 1 part. 



70 per cent, alcohol . . . . .10 parts. 

 Heidenhain's hsematoxylin- 



Hsematoxylin ..... 1 grm. 



Absolute alcohol . . . . .10 c.c. 



Distilled water . . . . . 90 



Thymol 1 crystal. 



Dissolve the heematoxylin in the absolute alcohol and then add 

 the distilled water. 



(5) Differentiate in the same solution as was used in (3) for 

 mordanting. 



