ZOOLOGY AND BOTANY, MICROSCOPY, K1C 



735 



Pig. 85. 



When the section has been cut, and the knife carriage is being drawn 

 back, the arm on the milled head is carried backwards, thereby turning 

 the milled head and raising the material for outting. The automatic 

 action can be thrown out of gear as desired, enabling the milled head to 

 be rotated by the fingers as usual. 



Darlaston Section Cutter.— This section cutter (fig. 85) is made of 

 a solid brass rod 1| in. diameter, with a well |^ in. diameter. It is 

 claimed by the designer that sections can be 

 cut with rapidity and accuracy, on account 

 of the solid nature of the construction. It is 

 made by Watson and Sons. 



(4) Staining- and Injecting-. 



Intra-vitam Staining of the Retro- 

 cerebral Apparatus of Rotifers.* — P. M. de 

 Beauchamp, in some further observations on 

 the retro-cerebral apparatus of Rotifers, states 

 that outside the sac, properly so-called, is a 

 second formation having quite different ana- 

 tomical characters. This subcerebral gland, 

 which as a rule is only detectable in sections, 

 becomes easily visible in the living animal 

 by means of intra-vitam stainingwith neutral- 

 red or with brilliant Kresyl blue. 



New Method of Staining Plasma Cells.f — F. Federici prepares 

 hot saturated aqueous solutions of safranin 0, G-riibler, and of " Licht- 

 griin." 60 c.cm. of the former are mixed with 20 c.cm. of the latter. 

 The precipitate which forms is filtered off, the filtrate constituting 

 solution A. The precipitate on the filter is washed several times with 

 distilled water, and is then dissolved in 50 c.cm. of ordinary alcohol : this 

 forms solution B. The final solution is made by mixing Mayer's 

 hasmalum 40 c.cm., solution A 40 c.cm., and solution B 20 c.cm. 



In the final solution the sections are placed for 1-3 hours. On 

 removal they are washed for a few seconds in 1 p.c. iron-alum, then in 

 distilled water, after which they are placed in absolute alcohol. Much 

 safranin is herein removed, and when the. sections have assumed a green 

 tint the differentiation may be assumed to be complete. They are then 

 passed through bergamot-oil, xylol, and finally mounted in balsam. By 

 this method it is claimed that the nuclei are stained blue, the connective- 

 tissue green, the cell protoplasm greenish-blue, the protoplasm of the 

 plasma cells (Mastzellen) pink, and their basophile granules red. 



Bielschowsky's Method of Staining Nervous Tissue.^ — R. Legendre 

 has used this method with success, and finds that he obtains better 

 results therefrom than from the procedure of Ramon y Cajal. Three 

 modifications are given. The technique of the first consists (1) in 



* Cornptes Rendus, cxliii. (1906) p. 249. 

 t Anat. Anzeig., xxix. (1906) pp. 357-61. J Tom. cit., pp. 361-7 (2 figs.). 



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