168 IMBEDDING METHODS. 



Row, Cambridge, price 5, or by Messrs. Swift and Son, or 

 by Jung) is only adapted for cutting paraffin sections (Mr. 

 Swift has shown me an arrangement for inclining the knife 

 so as to give it the position required for cutting celloidin ; but 

 I feel pretty sure that this will prove a failure in practice). 

 This instrument is extremely simple and extremely rapid, and, 

 what is more important, cuts more level series of sections than 

 any other microtome I am personally 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 arrangement allowing the precise orienta- 

 tion of the object. (This, as well as the entire instrument, is 

 manufactured in France by Dumaige, 9, Rue de la Bucherie, 

 Paris, or Messrs. Swift on request will furnish such an 

 arrangement, or it may be obtained, with or without the 

 entire instrument, from Jung, of Heidelberg.) 



It has been objected to this instrument by Schiefferdecker 

 (see Zeit. f. wiss. Mik., ix, 2, 1892, p. 171, a description and 

 criticism of the instrument as made by Jung) that it does not 

 cut plane sections, but sections having the form of segments 

 of a cylinder. This is true ; but it does not therefore follow, 

 as Schieffer decker concludes, that the instrument is inappli- 

 cable to many morphological purposes, and especially to 

 embryological research. In practice, the slight deviation of 

 the sections from a plane figure is found to be quite inappre- 

 ciable, and therefore unimportant. The chief defect of the 

 instrument from the point of view of the morphologist is that 

 it will not cut through a sufficiently lengthy series of sections 

 without having the object-holder readjusted. Now readjust- 

 ment of the object-holder is a ticklish piece of work, even 

 with the precise and well-situated Naples object-holder 

 mentioned above in connection with the Thoma microtome ; 

 much more is this the case with the relatively imperfect and 

 ill-situated object-holders supplied with the Cambridge micro- 

 tome. An ideal microtome ought to be able to section at 

 least a centimetre of tissue without readjustment ; the Cam- 

 bridge will only manage about a millimetre. 



For object-holders see the price list of JUNG ; also a paper 

 in Zeit.f. wiss. Mik., vii, 2, 1890, p. 165. 



Lastly, I would call attention to the MINOT microtome made 

 by E. Zimmermann, Mechaniker, 37, Halle'sche Strasse, 



