s 



ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



559 



poses a modification of the Roy model. It consists of a foot-plate 

 about 3 cm. long, attached to a screw clamp which serves to fix the 

 instrument to the bench and supporting a slot for the reception of the 

 nozzle of the ordinary spray apparatus attached to its upper surface. 

 The foot-plate supports the freezing-plate (5 cm. by 2 to 2*5 cm.) by 

 means of a short upright (about 2 cm.) The under surface of the 



Fig. 138. 



freezing -plate is traversed by several metallic ridges. The microtome, 

 which is made by Leitz, is constructed entirely of steel and iron, and is 

 nickeled. 



C4) Staining 1 and Injecting". 



Staining Nervous Tissue with G-allein.* — H. Schrotter finds that 

 gallein, a pigment belonging to the eosin group, stains the medullary 

 sheath of nerves very well. The dye is dissolved in boiling water. 



Sections of spinal cord are immersed in the solution for 15 to 20 

 minutes, and then differentiated in a 5 p.c. solution of soda. After 

 washing in water and dehydrating in absolute alcohol they are treated 

 with carbol-xylol. The medullary sheaths and medullated. fibres are 



* Centralbl. allgem. Pathol, u. pathol. Anat., xiii. (1902) pp. 299-300. 



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