742 SUMMARY OF CURRENT RESEARCHES RELATING TO 



placed for a few seconds in a 1 per cent, alcoholic solution of caustic 

 potash, and washed in a large quantity of water. The white sub- 

 stance then appears to the naked eye blue or violet, and the grey 

 substance red. With high powers one can see in transversely divided 

 fibres the axis-cylinder red, while in some fibres the whole medullary 

 sheath is composed of " cyanophilous," in others of " erythrophilous " 

 substance, or, again, the sheath is composed of concentric layers of 

 blue and red stained substances. In the grey substance of the spinal 

 cord Gerlach's network of delicate fibres is stained blue or violet on 

 a red ground. 



New Method of Staining the Spinal Cord.*— Prof. A. Adam- 

 kiewicz finds that by staining with saffranin and methylen-blue, 

 individual segments of the cord can be differentiated. These 

 " chromoleptic zones " are situated in general round the grey sub- 

 stance, following the outer contour of the cord. They also occupy the 

 internal part of the posterior fasciculus, and the part of the lateral 

 fasciculi which occupies the angle between the anterior and posterior 

 cornua. The non-chromoleptic zone forms a ring round the periphery 

 of the cord. 



Staining the Axis-cylinder of MeduUated Nerve-fibres.t — As 

 the result of his investigations, Dr. C. Kupffer finds that the axis- 

 cylinder contains the nerve-fibrils, which float loose in nerve-serum. 

 A compact axis-cylinder is an artificial product. To demonstrate the 

 nerve-fibrils in the axis-cylinder, the nerve is fixed on a cork and 

 placed for two hours in a 1/2 per cent, solution of osmic acid, washed 

 for two hours with distilled water, stained for 24-28 hours in a 

 saturated solution of acid fuchsin, washed for 6-12 hours in absolute 

 alcohol, clarified with oil of cloves, imbedded in paraffin, and cut. 

 The fibrils in the axis-cylinder are stained bright red, and appear in 

 cross section as stained points. 



Staining Desmids. — Mr. W. B. Turner sends us the following 

 process for staining desmids without contraction of the endochrome. 



When quite fresh gathered, wash and place in a solution of 

 chromic acid, so weak that it requires three days to decolorize a large 

 desmid. When the colour has gone, wash well in at least two waters 

 and stain with anilin. Fix with a little tartaric or weak nitric acid. 

 Then wash and mount in camphorated or carbolized water (about 

 10 to 90 per cent, distilled water). 



All fresh- water algae seem to do well under this process, including 

 the delicate Draparnaldia, which entirely fail after a little time in the 

 ordinary fluids. 



Boro-glyceride for Mounting.:): — Mr. A. P. Wire has for two 

 years experimented on this substance, and with, at present, such good 

 results, that he considers it worthy of extended trial. Boro-glyceride 

 is composed of boracic acid and glycerin, and exists in two forms, the 



* SB. K. Akad, Wiss. Wien, Ixxxix. (1884) p. 245. 

 t SB. K. Bayer. Akad. Wiss., 1884, pp. 466-75. 



% Journ. of Proc. Essex Field Club, iv. (1885) pp. Ixxix.-lxxx. Sci. -Gossip, 

 1885, pp. 139-40. 



