134 IMBEDDING METHODS. 



down various forms will be found almost equally convenient. 

 Zeiss makes a good one, Schanze, of Leipzig, makes a good 

 one. Reichert, of Vienna, makes a good one. All these are 

 relatively cheap, and being at the same time perfectly efficient 

 for easy work, maybe recommended. Amongst more precise 

 instruments I recommend the following: The Thoma sliding 

 microtome. If the student will obtain from R. Jung, Mechaniker 

 in Heidelberg, a Thoma microtome, medium size (No. 2 a or 4), 

 with the newest Naples object-holder and newest form of knife 

 and knife-holder, he will, in my opinion, be possessed of one 

 of the best of all-round microtomes. 



This instrument is described in Journ. Roy. Mic. Soc. (N.S.), 

 vol. iii, p. 298 ; the new Naples object-holder (which I consider 

 essential for the zoologist) is described and figured p. 915. 



The Becker microtome is considered by many good workers 

 to be an improvement on the Thoma model. It is essentially 

 on the same principle, but possesses a mechanical arrangement 

 for moving the knife-carrier. This, I think, is certainly an 

 advantage. A minor point is that the instrument is somewhat 

 cheaper than the Thoma form. It is made by Aug. Becker, 

 Gottingen. Descriptions of two forms (Spengel and Schief- 

 ferdecker) will be found in Journ. Roy. Mic. Soc., 1886, pp. 884 

 and 1084. 



Both these are admirable all-round microtomes, that is to 

 say, adapted to the most various kinds of work, and in par- 

 ticular equally adapted for paraffin sections and for celloidin 

 sections. There remains to be mentioned an important form 

 that is adapted for paraffin sections alone. This is the 

 beautiful Cambridge rocking microtome (furnished by the Cam- 

 bridge Scientific Instrument Company, St. Tibb's Eow, 

 Cambridge, price 5). This instrument is extremely simple 

 and extremely rapid, and, what is more important, cuts better 

 and more level series of sections than any other microtome I 

 am acquainted with. It should be fitted with the improved 

 moveable object-holder of Henneguy and Vignal (Compt. 

 Rend. Soc. Biol., 1885, p. 647), or some equivalent arrange- 

 ment allowing the precise orientation of the object. (This, as 

 well as the entire instrument, is manufactured in Franco 1 > y 

 Dumaige, 9, Rue de la Bucherie, Paris.) 



264. Imbedding Methods may conveniently be divided into 



