110 SUMMARY OF CURRENT RESEARCHES RELATING TO 



7. Treatment with acetic acid : 5 drops in 10 cm. distilled water 

 only until red-brown colour changes to yellow. 



8. Reduction in 4-5 p.c. formalin of the more firmly combined 

 silver (i.e. with the neurofibrils). Control under low magnification 

 until the nuclei appear unstained on a brown and black background. 

 Failure is denoted by nuclei more or less blackened and Nissl's spindles 

 in the cytoplasm. It is impossible to exactly control reduction in blocks, 

 which take from 1-6 hours according to size. A small piece of the 

 margin should be teased and examined. 



8a. Imbed in paraffin with melting point of 45°-50°. 



9. Fixation of the silver picture : All sections obtained in any way 

 and treated as above are washed in tap water for 1-2 hours, and placed 

 in a faint yellow watery gold chloride solution (1-0 ■ 5 p.c), neutralised 

 with lithium carbonate. The groundwork varies with the reaction of 

 the gold solution, red if acid, faint blue if alkaline or neutral, whilst the 

 impregnated fibrils are deep reddish violet or dark blue. 



10. Wash for a short time in tap water, then in 5 p.c. sodium 

 carbonate for 5-15 minutes, and finally in tap water for 6-12 hours 

 with frequent changing. 



11. Dehydrate ; clear in xylol. Mount in balsam without applying 

 any heat. 



Note. — If the neurofibrils do not stain by this method, the tissue is 

 not spoilt for other staining methods. 



Staining of Spirochaeta vel Spironema Pallida.* — El. Metchnikow 

 and Em. Roux remark that too much importance should not be attached 

 to the tint assumed by the Spirochceta pallida when stained by Giemsa's 

 method, nor to the number of turns of the spiral. They accept the 

 view that the Spirochceta of Schaudinn is the cause of syphilis, and regard 

 the disease as a chronic spirillosis with relapses. 



It has been recently suggested to alter the name to Spironema 

 pallida, on account of the numerous differences between the microbe of 

 syphilis and true Spirochcetce, such as plicatilis and ref ring ens. 



Demonstrating the Parasites of Smallpox.! — Siegel recommends a 

 mixture of 7 parts of eosin (1 : 15000), and 1 part of Giemsa's azur ii. 

 (1 : 1000) for staining Guarnieri's bodies. The sections are left in the 

 mixture for 2 hours, and are then mounted in balsam. The parasites are 

 extremely small, and sporulate in the cytoplasm, a point which distin- 

 guishes them from the sporozoon of foot-and-mouth disease, which 

 sporulates in the nucleus. 



Ambronn, H. — Ueber pleochroitische Silber-Xristalle und die Farbung mit 

 Mitallen. 



[With suitable treatment, anistropic and pleochroic crystals are formed from 

 solutions of silver nitrate ; hence there exists a labile form of silver the 

 crystals of which do not belong to the regular, but to another (possibly 

 the rhombic) system.] Zeitschr. wiss. Mikrosk., xxii. (1905) pp. 349-55. 



Heidenhain, M. — TJeber die Massenfarbung Mikroskopischer Sennit te auf Glim- 

 merplatfen. 



[Treats of the author's method of staining numerous sections on mica plates 

 for class purposes.] Tom. cit., pp. 330-6 (2 figs.) 



* Ann. Inst. Pasteur, xix. (1905) pp. 673-98 (2 figs..) 



t Abhandl. k. Preuss. Akad. Berlin, 1905. See also Brit. Med. Journ. (1905) 

 ii. Epit. 260. 



