380 SUMMARY OF CURRENT RESEARCHES RELATING TO 



u plate C. This acts both as a dial and a support for the framework 

 and the bottle I). The dial face C is perforated near the periphery by 

 a series of holes for pegs, which, as the drum revolves, strike a lever,, 

 and so cause the tap E to open and let out some of the fixative from 

 the Marriotte's bottle into the beakers. The beakers, which contain the 

 embryos, are ranged round the margin of a divided circle drawn on the 

 table F. It may be seen that, according to the strength of the fixative,, 

 the amount of fluid in the beakers, and the number of pegs inserted in 

 the dial face, almost any desired fixation may be obtained for any one 

 or more sets of embryos. For further details of this ingenious 

 apparatus the original should be consulted. 



Preparing Geim Cells of Pedicellina Americana.* — L. I. Dublin 

 fixed the material in corrosive sublimate with 5 p.c. acetic acid. The 

 stains employed were Heidenhain's haematoxylin, Auerbach's fluid, 

 thionin, and Flemming's triple stain ; but the first gave by far the best 

 results. The colonies were imbedded and sectioned en masse, and in 

 this way there were obtained on the same slide, male and female 

 individuals of all ages. 



Removing Avian Blastoderms.f — E. A. Andrews finds that by the 

 following method good preparations of blastoderms can be obtained. It 

 consists essentially in separating the blastoderm from the vitelline 

 membrane and of fixing it partially, and then separating it from the 

 yolk while the latter is still fluid. 



To accomplish this result, picro-sulphuric acid is injected between 

 the blastoderm and the vitelline membrane. When the blastoderm is. 

 partially fixed and become coherent, it is removed with the yolk. 



The pipette used has the upper part of sufficient size to hold a fair 

 quantity of fixative, while the lower end is drawn to a point, the- 

 extremity being bent at an angle. 



Examination of Bone Marrow.J — C. Price Jones obtains marrow 

 from ribs or vertebrse by squeezing it out of the bone with forceps and 

 transferring on a platinum loop to the following dissociating fluid. The 

 latter is prepared by diluting glycerin with ammonia-free distilled 

 water to form a 10 p.c. solution, and titrating this against decinormal 

 sodium hydrate, using phenolphthalein as indicator. The initial reaction 

 of this solution varies from +0*1 to -f-0'5 (Eyre's scale), and has a 

 specific gravity of 1*029 at 15 '7° C. A loopful of 10 p.c. glycerin is 

 placed on a coverslip, and to this a loopful of the marrow emulsion is. 

 added and spread over the surface of the slip. The film is then air- 

 dried and afterwards fixed and stained with the Jenner bloodstain. It. 

 is then washed with distilled water, dried, and mounted. Care should 

 be taken to avoid making the emulsion too concentrated or the films 

 too thick. 



Fixation of Tissues by Injection into the Arteries.§ — B. D. Myers, 

 is enthusiastic' over the procedure he adopts for fixing tissues. The 



* Ann. New York Acad. Sci., xvi. (1905) pp. 1-G4 (3 pis.), 

 t Zeitschr. wies. Mikrosk., xxi. (1904) pp. 177-9 (1 fig.). 

 J Brit. Med. Journ., 1905. i. p. 400. 

 § Johns Hopkins Hosp. Bull., xvi. (1905) pp. 6G-S (1 fig.). 



