CUTTING SE( TIO& - OF THE EYE. 313 



allowed to dry. In the mean time ; i solution of alum as fol- 



lows: Take 35 grams of alum, and after ii has been thoroughly 

 pounded in a mortar pour ii into -li—i ill<-<l water. I 



this solution add potash until a precipitate is formed, which 



will not dissolve upon stirring and standing. 



" Pour the alum solution thus made on to tin- hematoxylin 

 residue, and allow it to macerate for three <>r four days in :i 

 warm room. Then filter the hematoxylin solution into :i bottle 

 provided with a closely-fitting stopper, and add to it 10 cc of pure 

 glycerine and 100 c< . of 90 per cent spirit. (The residue need not 

 be thrown away, for it can lie macerated again with alum solution 

 for a week or more, and a good Btrong stain obtained as bef< 



Winn tin- solution is thus made it should lie well shaken and allowed 



to -land tor M ■ w< eks l" tor.' being used. This solution of haema- 



toxylin improves considerably with age. The oldest I have was 

 made about twelve months ago, and is by tar the best. 



•• 'The ha matoxylin stain produced by this recipe posa ssi ssevi 

 advantages over others. In most cases it differentiates the tissues 

 admirably; nuclei stain deeply, cell protoplasm faintly; it seems to 

 last a long time without showing signs of fading, and, a- it i 

 trates well, it i- \ ery useful for staining in hulk.'' 



Dr. J. 8. Kingsley's* method of preparing and cutting the i ggs and 

 embryo eyes of the shrimp, which will also appl} to the embryonic 

 eyes of insects, is as folloM s: 



The c\ es were hardened i>\ means of Pen nyi's fluid, followed by 

 alcohol of increasing strength, a process which works well with 

 almost all A.rthropod tissues. In most instances, they were stained 

 entire with Grenacher's alum-carmine, though in some instances 

 EQeinenberg's hematoxylin or Grenacher's borax-carmine were em- 

 ployed In the later stages, when- the deposition of pigment in the 

 eye interfered with a char \ ision of all tin- structures (one. rned, the 

 foil, win-- course was adopted: The eyes were sectioned as usual, 

 the sections being fastened t>> the slide with May. r's albumen fix 

 ative. After wetting the paraffine and allowing the sections to drop 

 into die adhesive mixture, the embedding material was dissolved ill 



turpentine, and this in turn was washed away with al( 95 per 



cent). The section- were then covered with a mixture of < qua! parts 

 of nitric acid and 95 per c nt alcohol, which was allov main 



until the pigment was removed, — a process requiriug from ten to 

 fifteen minutes. The slide was next washed wi;' alcohol, 



and the sections stained deeply with Kleinenberg's heinatoxj lin, and 



* .1 



Journal of Morphology, Boston, i vx 7, 49. 



