1042 SUMMARY OF CUKRENT RESEARCHES RELATING TO 



Fur Ptainin'T, Gerlacb's ammonia-carmiue is most recommended. 

 The sections may be stained in 3 to 5 minutes, if placed over a water- 

 bath filled \\itli boiling water. Lowenthal's picrocarmine, Czokor's 

 cochincal-alum solution, Bismarck brown, nigrosiu, and Grcnacber'salnm- 

 carmino arc also mentioned favourably. For staining the nervc-slicatbs, 

 osmic acid (osmic acid 1 per cent. + glycerin + ammonia), and Golgi's 

 sublimate and silver methods arc also alluded to. Palladium and gold 

 and Weigert's method are mentioned. 



Methods for Examining the Structure of the Cerebrospinal Nerves-* 



]VI, L. Potruuc found that the two following methods were the 



best for investigating the structure of the intracranial and spinal 



nerves : — 



(1) Bichromate of potash, or MuUer's fluid, and nitrate of silver. The 

 pieces of nerve were kept in a 2 per cent, solution of the bichromate, or iu 

 Miiller's fluid, frequently changed, for at least two mouths. The harden- 

 incr was accelerated by keeping the fluids at a temperature of about 25' C. 

 After this the pieces are placed for 24 to 48 hours in 0*75 per cent, 

 solution of nitrate of silver and kept in a warm place. The sections are 

 washed several times, to free them of excess of nitrate of silver, with 

 ordinary spirit, and finally with absolute alcohol. They are then passed 

 through creosote and turpentine oil successively, and having been placed 

 on a slide, are covered over with dammar merely (no cover-glass). The 

 disadvantages of this method are the copious precipitate on the surface 

 of the sections and the inconstancy of the staining. 



(2) Bichromate of potash, or Muller's fluid, and sublimate. The 

 pieces are first hardened as before, and then are placed by degrees in 

 0-35-0 -5 per cent, sublimate solutions, which must for the first 10 

 days be renewed daily, and afterwards every third or fifth day. In this 

 solutioB the pieces must remain for at least two months. The further 

 treatment is as before, except that the copious use of water is required 

 before the sections are placed in spirit in order to prevent the precipitate 

 on their surface. 



The foregoing methods may also be used for isolation of the 

 elements : — (1) The pieces hardened in bichromate are thoroughly 

 stained with ammonia-carmine, picrocarmine, chiuolein, or metliylen- 

 blne, and then dissociated in glycerin or some other suitable medium. 

 (2) The preparations are macerated in Eanvier's one-third spirit. Small 

 pieces are then shaken up in a test-tube with a little water, to which 

 picrocarmine and afterwards osmic acid arc added. 



Making Preparations of Bone and Teeth and retaining their 

 soft parts.t — I>r, L. A. "Weil takes only fresh, or nearly fresh, teeth, 

 and in order to allow reagents and stains to penetrate into the pulp 

 cavity, divides the tooth immediately after extraction with a sharp 

 fret-saw, below the neck, into two or three pieces, " allowing water to 

 trickle over it the while." The pieces are then laid in concentrated 

 sublimate solution for some hours to fix the soft parts. After this they 

 are washed in running water for about one hour, then placed in 30 per 

 cent, spirit, which in 12 hours is changed to 60 per cent., and again 

 after a similar period for 70 per cent. Then, in order to remove the 

 black sublimate precipitate, the teeth are laid for twelve hours in 90 per 



♦ Interaat. Monatschr. f. Anat. u. Physii-l., v. (1888) Heft. i. 

 t Zeitschr. f. WisB. Mikr., v. (1888) pp. 2U0-2. 



