cxii Journal of Comparative Neurology. 



new sheath. When the nuclei begin mitotic multiphcation a strong 

 connective tissue sheath is formed about the persistent axis cylinder. 

 A protoplasmic sheath appears inside the sheath of Schwann, this be- 

 gins to grow perijjherally about, the axis cylinder. This process is 

 supposed to introduce the formation of the sheath. In the vicinity 

 of the regenerating axis cylinders granulation tissue appears, in which 

 the nuclei arrange themselves in longitudinal series. These nuclei 

 are not only products of the neurilemma nuclei recognized by their 

 long form, but oval and spherical nuclei also occur. The nuclei are 

 not found to have any part in the restoration of the fibre. The fibre 

 bundle finally reaches the peripheral stump which, at this period, con- 

 sists only of decomposed clumps of myelin within the shrunken 

 sheath. No traces of axis cylinders are found in it. 



A New Fixing Fluid. 



Gustav Man describes a fluid composed of Absolute alcohol loo 

 com. picric acid 4 grm. corrosive sublimate 15 grm. Pieces should 

 not exceed i cm. in thickness and are left 12-24 hours. Then wash 

 in running water and place in 30 per cent, alcohol with tincture of 

 iodine sufficient to produce a brown color, for 12 hours, after which 

 the tissue is hardened gradatim in alcohol and imbedden in paraffin. 



A shorter method is to wash in absolute alchohol for 10 hours, 

 changing the fluid at least once and then, after sectioning, treat the 

 sections with iodine and iodide of potash solution. It is stated the 

 plasma and nuclei are well fixed with slight shrinkage and the cell 

 outlines are well brought out. Anat. Anzeiger. VIII, 12-2J. 



The Brain of Birds.' 



The two installments of Dr. Brandis' investigations which have 

 thus far appeared are characterized by a painstaking thoroughness 

 which wins for them a very high place in the literature of this diffi- 

 cult field. The brains were hardened in Miiller's fluid and imbedded 

 in celloidin. Sections were stained by Weigerts' haematoxylin 

 method and VVolter's modification of Kultschitzky's method, together 

 with carmine and nigrosin. The results secured seem to surpass by 

 far any illustrations of bird brains hitherto published. 



^Brandis, F. Untersuchungen liber das Gehirn der VogeL I. Theil: 

 Uebergangsgebiet vom Riickenmark zur Medulla oblongata, i plate Archiv f. 

 Mikroskopische Anatomie, Bd. XLI, Heft 2, April, 1893, PP- 168-195. ^^- Theil: 

 Ursprung der Nerven der Medulla oblongata, i plate. Do. Heft 4, July 1893, 

 pp. 623-649. 



