Literary Notices. xxxv 



against the light show the course of longitudinal and oblique fibre tracts 

 etc., in continuum. In consideration of the difficulty of drawing on oiled 

 paper, the following suggestions are here added : The microscope is 

 clamped upon a base which also carries a table similar to that of Giesen- 

 hageri but having a glass instead of wooden top. The paper is a very 

 fine and tough linen paper and is made up in tablets which are firmly 

 fixed to the drawing table. Through the tablet four small holes are 

 punched near the corners with a needle to serve for subsequent accurate 

 orientation. The outlines and details may be drawn in with ink quite 

 boldly and the sheets are numbered serially and also to correspond with 

 the sections. When the drawings are finished they are placed in sequence, 

 orientated bypassing pins through the perforations and the marginsglued. 

 The pad thus prepared is moistened with oil and becomes transparent. 

 After thorough drying the pad can be placed upon the table and a strong 

 light reflected from a mirror beneath enables one to produce an accurate 

 combination sketch. Great difficulty will frequently be experienced in 

 orientating the sections properly as there will probably be no easily rec- 

 ognized line lying exactly at right angles to the plane of section. Often a 

 line due to a notch in the microtome knife serves as a guide in 

 one direction. One may produce such a guide by plunging a hot 

 needle through two points in the preparation while still in the block 

 after orientating in the microtome. These needle holes should be per- 

 pendicular and parallel. This does not exclude irregularities growing out 

 of subsequent shrinking and in this as in all methods of geometrical recon- 

 struction the process must be "mixed with brains." It is probable that 

 every student of sections has employed some form of this method, but its 

 value should be recognized especially in the preliminary study of a 



series. 



Obregia' s sugar-ptiotoxylifi w^^^/wt/ of adhesion (Neurol. Centralblatt, IX, 

 lo, 1890.) is available for series with Weigert's method and other cases 

 where the complete integrity of a series is important. It consists in the 

 attachment of the sections, which maybe cut in ribbons if desired, on a 

 satin paper of the width of the cover glass to be used, by a solution of sugar 

 and dextrin. The upper surface is then flowed with alayer of photoxylin. 

 The solution of the sugar leaves the sections attached to a film of photox- 

 ylin with which they are carried through the subsequent treatment. For 

 securing complete section of large brains Lissauer has advised flowing the 

 surface of the paraffin block with celloidin (or photoxylin), cutting with a 



