330 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Simple Cooler for Use with the Microtome.* — C. Grave and 

 0. C. Glaser describe the above apparatus which they have found of 

 great service. It consists essentially of a hollow truncated pyramid, 

 open at both ends and suspended in an inverted position from a 

 standard, so adjusted that the lower end of the shoot is at a convenient 

 distance above the knife of the microtome. At the upper end of the 

 inverted pyramid, and surrounded by it, is a tray, whose dimensions are 

 less than those of the base of the shoot. This tray is filled with crushed 

 ice, and from one corner of it a drain leads the water to the escape from 

 the lower end of the air-channel. At that point a rubber tube connects 

 the pipe with a suitable receptacle. When the air of the room strikes 

 the melting ice in the tray it is chilled and immediately falls between 

 the tray and the walls of the pyramid. In this a constant stream of 

 coid air pours from the lower end of the shoot, and as this may be placed 

 directly above the paraffin-block and knife-edge, both of these latter are 

 cooled, and so make it possible to cut sections very much thinner than 

 the unmodified temperature of the room would allow. The extent to 

 which it is desirable to cool the paraffin and knife varies with each specific 

 case, but the cooler is adjustable in at least two ways. In the first place, 

 the distance of the block from the end of the shoot can be changed 

 within comparatively wide limits ; in the second place, the temperature 

 of the air delivered may be further lowered by the addition of common 

 salt to the ice. The authors record a case in which the material could 

 not be embedded in paraffin of a high melting-point, and it was im- 

 possible in the ordinary way to cut sections even as thin as 12 micra. 

 With the aid of the cooler, however, a perfect series 3 micra in thickness 

 was easily prepared from the same block of 45° to 48° paraffin. The 

 dimensions of apparatus are: base, 12 '5 x 8*7 in. ; truncated apex, 

 6'1 X 2*1 in.; ice-tray, 8'8 x 8*oin. 



(4) Staining- and. Injecting-. 



Demonstrating the Presence of Capsules in Bacteria. f — L. Gozony 

 shows that the capsules of the bacteria of hasmorrhagic septicemia are 

 readily demonstrated by the Indian ink method. Reproductions of photo- 

 graplis of films of Bacillus avisepticus and B. suiseptlcus are given. 



Differentiation of Cells in the Cerebrospinal Fluid by Alzheimer's 

 Method. J — D. K. Henderson and Winifred Muirhead say that the 

 technique of this procedure is not difficult. It consists in centrifuging 

 :^) or 4 c.cm. of the cerebrospinal fluid with double the quantity of 96 p.c. 

 alcohol for from one-half to one hour, depending on speed of the centri- 

 fuge. By this means the proteid is coagulated into a hardened plug. 

 It is then still further dehydrated and hardened by means of pouring on 

 absolute alcohol and then equal quantities of absolute alcohol and ether, 

 each for a variable number of hours depending on the thickness of the 

 plug. The plug is then loosened by means of a fine flattened platinum 

 needle embedded in celloidin and cut in sections of 15 />t in thickness. 



* Biol. BuU., xix. (1910) pp. 240-2 (1 fig.). 



t Centralbl. Bakt. Ite Abt. Orig., Ixviii. (1913) pp. 549-7 (3 figs.). 



X Bev. Neurology and Psychiatry, April 1913. 



