IMBEDDING MKI'tlODS. 79 



small objoofcs bs placed in any desired position nnder the 

 microscope {Jourii. Roy. Mic. Soc. [N.S.],u, p. 8S0). 



A liglitor form of "squares," made of brass, and devised 

 by Andees, Giesbrecht, and Mayer, is described l)c. cit. 

 (see Journ. Roy. Mic. Soc, 1883, p. yl3). A more compli- 

 cated sort is described by Wilson in Zeit. wiss. Mlk., xxvii, 

 1910, p. 228, for use with imbedded threads to serve as 

 orientation guides (see " Orientation") . 



Feankl [Zeif. ivLns. Mik., xiii, 1897, p. 438) builds up 

 boxes with rectangular blocks of glass, which may be found 

 convenient, but are more expensive than the metal squares. 



Sblbnka has describsd and figured another sort of apparatus having 

 the same object. It consists of a glass tubs, through which a stream 

 of warm water may be passed and changed for cold as desired, the 

 object being placed in a depression in the middle of the tube (see Zool. 

 Anz., 1885, p. 419). A simple modification of this apparatus, which 

 anyone may make for himself, is described by Andkbws in Amer. 

 Natural., 1887, p. 101 ; and a more complicated imbedding and orienting 

 box, seldom necessary, is described by Jordan, in Zeit. wiss. Mik., xvi, 

 1899, p. 32. 



To imbed in a watch-g^lass, the object, previously saturated 

 with parafRn, is put into a (preferably very concav.e) watch- 

 glass containing molten paraffin. After this has been solidi- 

 fied by cooling (see next chapter), a block containing the 

 object is cut out of it, and mounted on the object-holder of 

 the microtome (this is, of course, applicable to other masses, 

 such as celloidin). 



For imbedding very small objects in this way certain precautions may 

 be necessary in order not to lose them. Samtbb. {Zeit. wiss. Mik., xi, 

 1894, p. 469) saturates small unstained objects with parafiin that has 

 previously been strongly coloured with alkanna extract, and then imbeds 

 them in pui'e parafiin. Bhumbleb {ibid., xii, 1895, p. 312, and xiii, 1896, 

 p. 303) stains previously the oljjects themselves with eosin dissolved in 

 strong alcohol, and removes the stain from the sections with weak 

 alcohol. See also ibid., xiii, p. 200, a paper by Schydlowski; and in 

 Zeit. wiss. Zool., Iviii, 1897, p. 144, a process of Borgekt. 



BoRGEBT {Zeit. wiss. Zool., Ivih, 1897, p. 144) allows parafiin to solidify 

 in a watch-glass, bores a hole in it, and places the objects in the hole 

 with a little benzol, and puts the whole for a short time into a stove. 



A watch-glass provided at the bottom with a groove or trough, in 

 which small objects may be made to collect, is described by Lefidvrb, 

 Journ. App. Mic., v, 1902, p. 280 (see Joarn. Boy. Mic. Soc, 1903, p. 233). 



Latjterborn {Zeit. wiss. Zool., lix, 1895, p. 170) brings the objects 



