586 SUMMARY OF CURRENT RESEARCHES RELATING TO 



is weighed. To each pound one litre of water is added and allowed to 

 extract over night at room temperature. The solid matter is now 

 removed by straining through muslin, and the resulting fluid is heated 

 in the autoclave to 115° C. A sufficient quantity of acetic acid to 

 render Dhe hot fluid faintly acid is nest added, which causes the sus- 

 pended matter, starches, albumins, etc., to agglutinate into large masses, 

 rendering the passage of the fluid through filter paper rapid and easy. 

 The fluid thus obtained is rendered faintly alkaline to litmus, and 

 0-25" p.c. of glucose, 5 p.c. of glycerin, and 200 c.cm. per litre of a 

 2 p.c. slightly alkaline solution of plasmon are added. On the addition 

 of a white of an egg to each litre a further heating to 100° C. clears the 

 fluid, and on filtration gives a clear brown-coloured broth, which is 

 then distributed in flasks and sterilized by steaming for 30 minutes on 

 three successive days. Agar medium can also be made from this broth, 

 which gives an abundant growth of human tubercle bacilli having but 

 very slight adherence to the agar surface, and in consequence easily 

 lifted off with a coiled platinum wire, and floated on to the surface of 

 broth when it is desirable to grow the organism on fluid media. 



(2) Preparing Objects. 



Gametogenesis of Grantia compressa.* — A. Dendy obtained this 

 sponge from near the Plymouth Laboratory, from Drake's Island and 

 Rum Bay. A large number were microscopically examined in the 

 living condition, either by teasing, or by hand sections, or by pipetting 

 out the contents of the central gastral cavity, but search for living 

 spermatozoa was fruitless. The material that turned out satisfactory 

 was fixed either in strong Flemming's solution, or in a mixture of 

 Flemmin?;, formol, and sea-water. In the former case, it was graded 

 up after washing to 70 p.c. alcohol, in the latter it was preserved in 

 formol sea-water. 



The sections were for the most part cut of a thickness of 5/*, 

 and stained on the slide. Iron-brazilin gave excellent results, but 

 iron-haematoxylin was also used. For staining in bulk boraxcarmin 

 or paracarmin was employed, the latter being sometimes followed by 

 picro-indigo-carmin, but without much effect. 



(4) Staining- and Injecting-. 



Chromosome Complex of Culex pipiens.f— Monica Taylor fixed the 

 material in Benda's fluid, acetic bichromate, Gilson's mercuro-nitric, 

 Flemming, and Gilson-Petrunkewitsch, the two latter being the most 

 successful for the cytology proper ; the two former were useful for 

 interpreting cytoplasmic details. Thionin, iron-hrematoxylin, Mayer's 

 cochineal, Ehrlich hasmatoxylin, and safranin, were the stains employed. 

 Many slides were first studied in thionin, and then the coverslip removed, 

 the thionin washed out, the sections restained in iron-hajmatoxylin, 

 and comparisons made between the results of the two stains. Although 



* Quart. Journ. Micr. Sci., lxxxviii. Ser. B (1914) p. 319. 

 t Quart. Joum. Micr. Sci., lxxxviii. (1914) p. 379. 



