498 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Staining Spirilla in Sputum.* — L. Follet makes use of the followinsr 

 mixture : Ulycerin 4u grm., acid-fuchsin 2 grm., pure carbolic acid 

 J grm. Mix, and filter after sohition. The sputum to be examined 

 shoyld be recently expectorated, and preferably after fasting. Pick out 

 a fragment with a platinum needle, place on slide, and add thereto a 

 minute drop of stain. ^lix thoroughly and put on a coverslip and 

 examine. If a Uttle acid green dissolved in glycerin be mixed with the 

 sputum before the acid-fuchsin is used, a brownish hue is imparted to 

 the preparation ; and if a double-staining be desired, this maybe effected 

 by using in addition to the acid-fuchsin solution the following mixture : 

 Glycerin 40 grm., methylen-blue '2 grm., pure carbolic acid 0'5 grm. 



While this medium stains all the spirilla infesting the mouth, so 

 that ({uite swarms may be observed in the same field, there is no difficulty 

 in differentiating 2\eponema paJI kium. 



Another method given by the author is suitable both for fixed and 

 frt'sh films. This consists of chloroform 4(t grm., methylen-blue 2 grm., 

 acid-fuchsin 0'25 grm., pure carbolic acid 0-5 grm. 



The stained preparations must be thoroughly washed in running 

 water, and if need be in alcohol to remove excess of pigment. 



Orlean. a New Stain for Cork and Cuticula.f — P. Sonntag finds 

 that Orlean or Annattu, used for dying wool and silk, and for colouring 

 butter and cheese, makes a good stain for cork and cuticula. The 

 reagent used is a solution of Orlean extract (Extract-Orleans spirit, 

 spiss.) dissolved in alcohol and filtered. If this solution be applied for 

 ^1 hour to sections of Cystisus Laburnum, which are afterwards washed 

 in alcohol and then placed in water or glycerin, the cork-cells are found 

 to be stained orange-yellow, contrasting with the whiteness of the rest 

 of the tissue. 



Modification of Donaggio's Method for Staining Nerve-cells. | — 

 Andrea Tomaselli treats the material as follows : Pieces of nervous 

 tissue (spinal ganglia) are immersed in ammoniacal alcohol (absolute 

 alcohol 10(», anniionia 4-5 drops) for 6-7 hours. They are then im- 

 mersed in pure pyridine and kept at a temperature of 36-87° C. for two 

 days, the pyridine being very frequently changed, especially at first. 

 The pieces are then washed in running water for 2-3 liours. The after 

 treatment is the same as that in Donaggio's third method, i.e. the 

 material is treated with an acid solution of molybdate of ammonia for 

 12 hours, imbedded in paraffin, and the sections stained with thionin 

 (1:10,000). 



I^ Bielschowsky's Impregnation Method. § — F. K. Studnicka obtains 

 excellent results from Bielschowsky's impregnation method when dealing 

 with connective-tissue fibres in bone, dentine, and hyalin cartilage. The 

 procedure is as follows. The method of fixation is quite immaterial, 

 good results being obtained from alcohol, formalin, 4 p.c. nitric acid, 

 Muller's, Flemming's, Perenyi's, Mayer's, Kleinenberg's, and other 



* C.R. Soc. Biol. Paris, Ixii. (1907) pp. 567-8. 



t Zeitschr. wiss. Mikrosk., xxiv. (1907) pp. 21-4. 



i Op. cit., sxiii. (1906) pp. 421-2. § Tom. cit., pp. 414-20. 



