ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



1051 



The knife-carrier g terminates in front in two openings, through 

 which the knife is passed, and is there fastened by means of two screws. 

 The cup-shaped object-holder d fits accurately in the ring c. One-half 

 of the latter is movable and fixed by two screws, so that the preparation 

 may be placed in any desired position. The object is imbedded in the 

 usual manner in pure paraflfin, and is then melted in the cuj) filled with 

 hard paraffin. The cup is then fixed in the ring in such a manner that one 

 surface of the paraffin mass is parallel to the knife. When cutting, each 

 section is pushed off the knife by its predecessor, and adheres to it so that 

 a ribbon-like strip is produced, and this is taken upon a brush and placed 

 on the band li. This band moves over two rollers, one of which is attached 

 to the front side of the microtome, the other to the knife-carrier g. The 

 first section is stuck firmly to the band, the lower side of which is pulled 

 by the left hand, so that the whole series of sections eventually lie on the 

 upper side. 



Excellent sections of the frog's embryo, and series of sections of 

 the embryos of Erinaceus and Galliis domesticus, which are 15 mm. long, 

 have been prepared by this instrument, which is also said to work very 

 quickly, so that 1000 sections can be prepared in ten minutes. The fig. 

 represents the microtome about 1/5 its natural size. 



Hayes's Ether Freezing Microtome.— This instrument (fig. 219*) was 

 designed by Dr. E. A. Hayes with the object of affording to those who have 

 occasional need to cut sections of tissues for pathological investigations, &c., 

 with the means of doing so quickly, conveniently, and accurately. It is 



very compact, solidly constructed, and simple in plan. It freezes rapidly, 

 and permits sections of large surface to be made with precision, sections 

 1 in. X 5/8 in. having been cut by it without difficulty. 



It consists of a solid cast-iron base A, 10 in. x 4^ in,, which rests upon 

 a mahogany block. Extending the whole length of the upper surface of 

 the base is a V-shaped gutter, on the planed sides of which slides a heavy 

 metal block B, on the flat top of which the razor is secured (any ordinary 

 razor can be used), the tang being grasped between two flat pieces of iron, 

 which are pressed together by a winged nut C. The razor by this arrange- 

 ment can be secured at any desired angle to the direction of its motion to 

 and fro. 



The freezing chamber is formed by a short vulcanite cylinder D, its 



* The block is supplied by the author, but hardly does justice to the apparatus. 



