314 SUMMARY OF CURRENT RESEARCHES RELATING TO 



mixture should be well stirred daily, and kept in a warm room. The 

 mass to be cut is hardened in any desired manner, and fastened by 

 needles in the requisite position for cutting in a paper case the same 

 size as the well of the microtome. The celloidin solution is poured 

 in as free from bubbles as possible, and allowed to set slightly. The 

 paper case and its contents is then placed in a quantity of methylated 

 alcohol of 80°, not less, as otherwise the coUoidin becomes tough, and 

 not more, or it will dissolve it. It is left in this until of the proper 

 consistence to cut, about as firm as boiled egg albumen. If possible, 

 the sections should be cut under the surface of methylated spirit. 

 Katsch's machine is made for, and is simply perfect for this purpose, 

 but sections can be out very well if the whole surface of the micro- 

 tome in use is kept flooded with spirit. The sections can be stained 

 by any of the ordinary fluids ; the celloidin takes a slight stain, but 

 as it is perfectly amorphous it does not in any way interfere, and can, 

 of course, if the species of section admit it, be dissolved away by the 

 mixture of ether and alcohol. On the whole, it seemed about the best 

 thing for the purpose that he had met with, and members might judge 

 of its fitness by the fact that it enabled one to cut sections of the 

 whole eye, every structure remaining in situ, a feat he supposed 

 impossible with any other material." 



Gage's Imbedding-mass Cup.*— S. H. Gage describes the imbed- 

 ding-mass cup, shown in fig. 43, about 1/5 natural size. A is a 

 water-bath, into the top of which is firmly 

 soldered the cup B for the imbedding-mass, 

 having a fine wire gauze basket, suspended 

 by a stiff wire, for holding the tissue. The 

 cup is placed on one side of the water-bath 

 to facilitate the pouring out of the im- 

 bedding-mass. The apparatus may be heated 

 on a stove or by a gas or alcohol flame. 



Gage and Smith's Section-flattener.t— 

 S. H. Gage and T. Smith have devised a 

 section-flattener somewhat similar to that of 

 Andres, Giesbrecht, and Mayer,t but, as 

 they consider, simpler and applicable to 

 every form of section knife. 



The section-flattener (fig. 44) consists 

 of a rod b of spring brass about 5 mm. in 

 diameter, flattened on two sides 6 and d, extending parallel with 

 the edge of the knife, and projecting about 2 mm. beyond it. 

 Opposite the cutting edge the space between the rod and knife 

 is about 1 mm., while nearer the back of the knife the distance is 

 greater (D, a, b). At each end the rod is bent at right angles. 

 Next the handle it passes through a hollow cylinder d, into which it 

 is secured by a milled nut c. At the free end of the knife the rod is 



* Medical Student (N.Y.) i. (1883) pp. 14-16 (2 figs.), 

 t 'The Microscope,' iv. (1884) pp. 25-7 (1 fig.). 

 t See this Journal, iii. (1883; p. 916. 



Fig. 48. 



