ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



893 



Fig. 191. 



known as riband cutting, in which the sections, while still on the 

 knife, are made to adhere together by their adjacent edges, so that a 

 chain of sections in perfect continuity is produced. 



In order to effect this the objects must not be too large ; not more 

 than 3 or 4 mm. long or broad ; they must be imbedded in paraffin 

 and the form of the imbedding mass must be rectangular, as shown 

 in o, fig. 191. The knife k should 

 be placed at right angles to the 

 long axis of the microtome, the 

 same part of the edge s' being used 

 throughout ; the paraffin mass 

 must be so cut that the two sur- 

 faces a and b lie parallel to the 

 edge of the knife. The more 

 accurately this is carried out the 

 better the sections adhere. A 

 rapid to and fro motion of the 

 knife is recommended as being- 

 likely to produce better sections , 

 and also cause the edges to adhere better. "When a sufficient 

 number of sections have been thus obtained the chain may be laid 

 upon smooth white paper strips and then cut up into any desired 

 length. Schanze's microtomes are said to be more suitable for riband 

 cutting than Jung's, because the preparation always remains in the 

 same position, is raised by a screw, and the knife can be placed over 

 the same surface. With dexterity it is not difficult to make two 

 sections a second. 



Apparatus for facilitating the preparation of Serial Section?.* — 

 In order to facilitate the manipulation of series of sections, especially 

 of the nervous system, Dr. M. v. Lenhossek has constructed a tray of 

 perforated zinc, fig. 192, and subdivided into a number of compart- 



monts. Though the number and dimensions of these compartments 

 may be variod, the author's apparatus has sixteen compartments, the 

 diameters of which are 4 cm., and the depth about 1*5 cm. It is 

 also provided with two handles and four knob feet. If required for 

 watery solutions, the zinc may be japanned ; if for alcoholic, it is 

 advisable to leave the metal in its natural condition. 



* Zeitschr. f. WIss. Mikr., iii. (1886) pp. 5u-5 (1 fig.). 



