ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 155 



given off. They are then dehydrated, cleared up, and mounted in Canada 

 balsam. 



The preparations show the epiphysial cartilage to be of a dull pale 

 blue, while the remains of the cartilage between the lines of ossification 

 is of a deep blue colour. The newly-formed bone stains yellow, and the 

 blood-vessels have a brownish hue. The permanence of the stain seems 

 fairly good, as the author possesses specimens made six months ago which 

 have undergone no perceptible change. 



A modification of the foregoing method is also given. Instead of with 

 hematoxylin the sections are deeply staiued with methyl-violet and de- 

 colorized with picric acid until the blue colour is no longer given off. 

 After being mounted in Canada balsam the sections look green to the 

 naked eye. The cartilage remains, even to their least ramifications, are 

 stained deeply blue and surrounded by yellow layers of bone. In the 

 periosteal region the young bone-cells are of a greenish colour. The 

 epiphysial cartilage is pale yellow. In this modification the histological 

 details are wanting, and it is chiefly useful for demonstrating the difference 

 between periosteum and cartilage ossification under low powers. 



Staining- the Elastic Fibres of the Skin.* — Dr. K. Herxheimer 

 hardens his preparations in Midler's fluid ; his method will, however, 

 give good pictures after spirit, picric acid, and the chrom-osmic-acetic 

 acid mixture. The sections should not be more than 0'2 mm. thick. 

 They are stuck on with celloidin, and then stained for three to five 

 minutes with hasmatoxylin (1 c.cm. haamatoxylin, 20 c.cm. alcohol ab- 

 solute, 20 c.cm. H 2 0, 1 c.cm. lithium carbonate), but other watery solu- 

 tions may be used. The sections are then treated for five to twenty 

 seconds with chloride of iron solution. This last step requires some 

 care. Mount in balsam. The elastic fibres stain a bluish-black or 

 black, while the surrounding tissue is grey or bluish. By longer action 

 of the iron, so that the connective tissue is quite decolorized and a part 

 of the elastic fibres slightly pale, a contrast stain with carmine or Bruns- 

 wick brown may be used with advantage. The method can be em- 

 ployed for staining the nervous system ; for this two hours are required. 

 Instead of haBmatoxylin the author also uses anilin water gentian-violet. 



Staining Nerve-terminations with Chloride of Gold.f — Dr. G. 

 Boccardi recommends the reduction of objects impregnated by Ranviers 

 or Lo wit's gold chloride method to be done with oxalic acid of 0* 10 per 

 cent., or of 0* 25-0 "30 per cent. Another favourable reduction fluid 

 consists of 5 c.cm. pure formic acid, 1 c.cm. oxalic acid of 1 per cent, 

 and 25 c.cm. aq. destil. Pieces impregnated with gold chloride are to 

 remain in this fluid in the dark not longer than 2 to 4 hours. 



Demonstrating the Membrane of the Bordered Pits in Coniferse.J — 

 Dr. A. Zimmerman states that this membrane ouly requires staining for 

 its demonstration, and that hasmatoxylin is the best dye for the purpose ; 

 Bismarck-brown and gentian-violet are also capable of staining this 

 tissue, but are inferior to logwood. 



Material which has been preserved in alcohol is to be preferred. 

 The sections are placed in Bohmer's hematoxylin for 2-5 minutes only, 

 as a longer time stains the rest of the membrane, and it is advisable to 



* Fortschr. d. Med., iv. (1886) pp. 785-9. 



t Alboni Lavori eseg. nell' Istit. Fisiol. Napoli, 1S8G, Fasc. 1, pp. 27-0. 



J Zeitscli. f. Wiss. Mikr., iv. (1887) pp. 21G-7. 



