ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 107 



it in any way develop its special parts and orfjans. He followed pre- 

 vious investigators in this line of research, but somewhat modified the 

 technique. He used rabbits which were pregnant five to seven days, and, 

 after removing the blastocysts, immersed them in maternal Ijlood-plasma, 

 previously obtained by bleeding the animal. After an incubation at 

 89° '5 for 24 hours development was found to have occurred as shown 

 by the increased size of the embryo, and by the presence of numerous 

 mitoses. The author regards his results with complaisance, and states 

 that he is pursuing the subject still further, and is endeavouring to 

 ascertain if the plasma of the unfertilized female or of the male exercises 

 any inhibitory influence on the development of the blastocyst. 



(3; Cutting-, including" Embedding and Microtomes. 



Modification of the Burri Indian Ink Method.* — L. ^Y. Harrison 

 finds that collargol forms an effective substitute for Indian ink. A 

 suspension is made by adding 1 part of the powder to 19 parts of 

 distilled water in a black glass bottle, or a bottle covered with carbon 

 paper. After a few shakings the suspension is ready for use. It keeps 

 well for months. The films are made in the usual way, and the spiro- 

 chsetes appear as delicate spirals on a reddish-brown perfectly homo- 



geneous field. 



(4) Staining- and Injecting-. 



Staining Nerve-fibres with Neutral Red.j — J. Kublik demon- 

 strates the vitreous and fine nerve-fibres by means of neutral red, a 

 method discovered by S. Mayer. He uses a saturated solution of 

 neutral red in normal saline, and then dilutes from 10 to 15 times with 

 saline. The preparations when stained are washed in saline and then 

 treated with picrate of ammonium, after which they are mounted in 

 glycerin or in glycerin-ammonium picrate. 



Haemalum and Picrocarmin Staining Soiutions.J — T. G. de Groot 

 gives the following directions: — 1. Watery h^malum : Dissolve 0*1 

 grm. potassium f erricyanide in 20 c.cm. distilled water, add * 2 grm. 

 Griibler's haematoxylin, and, when this is dissolved, 40 c.cm. of distilled 

 water. Add 5 grm. alum, heat gently and make up with 50 c.cm. of 

 water. Cool and filter. 2. Alcoholic h^malum : In a 300 c.cm. flask, 

 place 2 c.cm. of hydrogen peroxide and 4 c.cm. of a 12 : 2 mixture of 

 70 p.c. alcohol and glycerin. Warm and add 0*5 grm. ha^matoxylin. 

 When dissolved add 60 c.cm. alcohol-glycerin, and, after shaking, 4 grm. 

 calcium chloride and 2 grm. sodium bromide. When this is dissolved 

 add 3 grm. alum and 100 c.cm. alcohol-glycerin. Warm to promote 

 solution. Then add 0*2 grm. potassium ferricyanide, 76 c.cm. of 

 alcohol-glycerin, and 3 grm. of alum. Cool and filter. 3. Alcoholic 

 hsemalum solution, 30 c.cm. ; alum, 4 grm. ; distilled water, 85 c.cm. 

 4. Picrocarmin : Place * 5 grm. carmin in 4 c.cm. distilled water warm. 



* Brit. Med. Journ., 1912, ii. pp. 1547. 



t Arch. Mikr. Anat., Ixsxi. (1912) pp. 74-81 (2 pis.). 



i Zeitschr. wiss. Mikrosk., xxix. (1912) pp. 181-5. 



