ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 499 



fluids. The material is decalcified in the usual way, but the author used 

 nitric acid with 3 p.c. alcohol. Both paraffin and celloidin sections can 

 be used. The sections, after thorough washing- in water, are placed in 

 3 p.c, silver nitrate solution for about 4 days. They are then washed 

 in distilled water, and afterwards transferred to an ammoniacal silver 

 solution, prepared as follows : to a 10 p.c. solution of silver nitrate a 

 40 p.c. solution of caustic soda is added drop by drop until a precipitate 

 is no longer produced. The sediment is then dissolved in ammonia. 

 The slightly yellowish fluid is filtered and made up to four times its 

 bulk with water. In this fluid the sections become darker, and of a 

 yellowish-brown hue. After washing they are placed in 10 p.c. formalin, 

 which turns them brown. After 5 minutes or so, they are washed, and 

 then placed in ^ p.c. gold chloride solution, in which their colour 

 becomes grey to black. They are next transferred to a 5 p.c. solution 

 of fixative soda, which renders them less .opaque as some of the un- 

 reduced silver is dissolved. Then follows a thorough washing in water, 

 alcohol, oil, xylol, balsam. 



The sections may be contrast-stained with advantage, e.g. with acid- 

 fuchsin or with Van Gieson's picric-acid — acid-fuchsin mixture. 



Demonstrating the Presence of Negri Corpuscles in Salivary 

 Gland of Mad Dogs.* — Elise Stefanescu fixed the material in formalin 

 and made frozen sections, which were stained by Mann's method 

 (methylen-blue and eosin) modified to suit the requirements of the 

 case. The sections were staining for 20-30 minutes. They were then 

 washed with water, dehydrated in alcohol, cleared up in xylol, and 

 mounted in balsam. The Negri corpuscles were stained red-violet, which 

 easily differentiates them from the blue colour of the cytoplasm. 



Studying Sympathetic Nervous System of Mammals.t — A. Kohn 

 used ral:)l)it embryos in his research and fixed the material for 24 hours 

 in the following fluid : 25 c.cm. of 5 p.c. aqueous sublimate solution, 

 75 c.cm. of 3i p.c. potassium bichromate solution, 5 c.cm. acetic acid. 

 After washing for 24 hours in running water the material was passed 

 through upgraded alcohols to 95 p.c. alcohol. To this last some tincture 

 of iodine was added, and, after sufficiently iodising the material, was pre- 

 served in 95 p.c. alcohol. The material was stained en masse with alum- 

 cochineal or with dilute hajmatoxylin, and in the latter case the sections 

 were contrast-stained with picro-f uchsin, eosin, Congo-red, etc. Sections 

 were also treated with Weigert's iron-hsematoxylin-picro-f uchsiu stain and 

 also by Ramon y Cajal's silver method. 



Demonstrating the Presence of Striated Muscle in the Thymus. J — 

 R. Weissenberg killed the fowls with chloroform and fixed the tissue 

 with some preparation of osmic acid, Flemming's strong solution 

 giving the Ijest results. Tellyesnicsky's fluid was also used. Sections 

 3 fji thick were stained with iron-h^ematoxylin or by means of Biel- 

 schowsky's silver method. The sections were mordanted for 4 hours, 



* C.R. Soc. Biol. Paris, Ixii. (1907) pp. 886-8. 



t Archiv Mikrosk. Anat. u. Entwickl., Ixx. (1907) pp. 266-317 (3 pis.). 



i Tom. cit., pp. 193-226 (1 pi.). 



