1-92 SUMMARY OF CURRENT RESEARCHES RELATING TO 



removed. If necessary, a drop or two of water can be added now and 

 then, io keep the air moist. Only plain water should be used. When 

 the sclerotium revives, the Plasmodium creeps on to the glass on either 

 side of the ring of paper,and the reversing currents can then be Been by 

 placing the tube on the stage of the Microscope and throwing the light 

 up through it from the mirror beneath. A 1-inch objective, focused on 

 the veins of the spreading plasmodium, shows the streaming movements 

 quite plainly. The sclerotium should be placed in the tube the day 

 before the plasmodium is required for exhibition. 



New Collecting Tube.*— A. M. Banta states that the pip 

 described below (fig. 21) is very useful for pond-life purposes, and will 

 collect any small or delicate object up to 6 or 8 mm. in diameter. 

 It is made from a calcium-chloride tube about 200 mm. long and the 

 ordinary 50 c.cm rubber bulb. The calcium-chloride tube used in 

 the pipette figured consists of a glass bulb about 35 mm. in diameter 

 blown in a glass tube of 16 mm. in diameter and about 120 mm. long. 

 One end of the tube is heated in the flame and drawn out to the desired 



rr» 



Fig. 21. 



diameter for the pipette-mouth. From the opposite end of the glass 

 bulb there extends a tube about 6 mm. in diameter suitable for attach- 

 ment of the rubber bulb. 



(2) Preparing- Objects. 



Demonstrating the Development of Trypanosoma lewisi in the 

 Rat-flea.f — E. A. Minchin and J. D. Thomson first extracted the 

 viscera of the fleas and then examined them under the Microscope. If 

 infected the cover-glass was removed and then dropped into a fixative, 

 while the slide is exposed to the vapour of osmic acid for 10 to 15 

 seconds, and then removed to absolute alcohol for about 15 minutes, and 

 then stained with Giemsa in the usual manner. For fixation of cover- 

 slip films Schaudinn's fluid or sublimate-acetic were used, but though the 

 results were good, Maier's modification of Schaudinn's fluid was after- 

 wards adopted (H 2 200 c.cm., CoH 6 100 c.cm., sodium-chloride 1*2 

 grm.,HgCl 2 10 grin.). The cover-slips are immersed in this fluid for 10 

 to 30 minutes or longer, and then passed through upgraded alcohols to 

 90 p.c, wherein they can be kept until it is convenient to stain them. 

 The cover-slip films were stained with Heidenhain's iron-hsematoxylin. 

 When this process was completed the cover-slips were rapidly passed 

 through Lichtgriin-picric-acid solution (Lichtgriin 1 grin., picric acid 



* Science, xl. (1914) pp. 98-9 (1 fig.). 



t Quart. Journ. Micr. Sci., lx. (1915) pp. 463-692 (10 pis. and 24 text figs.). 



