IMBEDDING METHODS. 89 



The Cambridge rocking microtome (furnished by the Cambridge Scientific 

 Instrument Company, Carlyle Road, 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 aui personally acquainted with. It 

 should be fitted with an adjustable object-holder, allowing of precise orienta- 

 tion of the object. This, I believe, has been done in the newest (1900) 

 .model. Or the object-holder of Henneguy and Vignal (Compt, Rend. Soc. 

 BioL, 1885, p. 647) may be added to it, (This, as well as the entire instru- 

 ment, is manufactured in France by Uumaige, 9, Hue 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.) 

 See also in Zeit. f. wiss. Mik., iv, 4, 1887, p. 465, the description of an 

 object-holder adapted to the rocking microtome by HASSELAEH ; further, the 

 price list of JUNG; also a paper in Zeit.f. wiss. Mik., vii, 2, 1890, p. 165. 

 Jung's form of the microtome is more expensive than the English one, but 

 contains several very useful improvements in details. 



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 in practice the slight 

 deviation of the sections from a plane figure is found to be quite in- 

 appreciable, and therefore unimportant. This slight defect has been over- 

 come in the special model of 1895; but this costs 8 10s., and for 

 ordinary work, such as does not require very large sections, may be dis- 

 pensed with. 



Rather more costly (8 15s.) is the MIXOT microtome made by E. 

 Zirnrnermann, Mechaniker, 21, Emilien Strasse, Leipzig. A description 

 and figures of this instrument will be found in Zeit.f. iciss. Mik., ix, 2, 

 1892, p. 176, or in Journ. Boy. Mic. Soc., 1889, p. 143. This microtome 

 cuts plane sections. It cuts with very great rapidity. It is said that 

 owing to the construction of the slide, which is subject to uncompensated 

 wear and tear, its work is liable to fail in accuracy. The object-holder 

 does not appear to be so scientifically constructed as the Naples one. Like 

 the Cambridge instrument, this microtome is only adapted for paraffin 

 work. 



MAYEE (Grundziige) gives the preference to the form of this instrument 

 made by A. Becker, of Gottingen, over that made by Zimmermann. 



The most beautiful of all these instruments is the REIXHOLD-GILTAY. 

 It is constructed on essentially the same principle as the Minot, but the 

 detail has been further elaborated, with the result of obtaining an instru- 

 ment that is at the same time more precise in operation and more resistant 

 to wear and tear, all working parts being compensated throughout. 



It has an arrangement for allowing the cutting of collodion material. I 

 -am unable to say whether this is a success. It is made by J. W. GILTAY, 

 Delft, and costs about 20. A description will be found in Zeit. f. wiss. 



