782 SUMMARY OF CURRENT RESEARCHES RELATING TO 



that are no thicker than the t^Vo or even the ^Vu- part of an inch ; 

 but this requires management, much depending on the force with which 

 the screws K K pinch the wood. 



It is not an easy matter to procure an edge sufficiently fine for the 

 above purpose, but, with the very best possible, thin slices have a ten- 

 dency to curl up into rolls, so as to be unfit for the Microscope ; to 

 prevent which a very slender spring is made to press gently on that 

 extremity of the slice where the incision begins, so as to keep it fiat 

 to the cutter ; when this spring is set to its proper position, it is fixed 

 to it by the small finger-screw I. And, lest the action of this spring 

 should destroy the slice after it is wholly cut, and in passing over the 

 extremity of the cutter, the piece e e (which turns with the cutter) is 

 fixed by the nut G into such a position that in passing under the spring 

 it raises it, and relieves the slice at the very instant that the cutter has 

 wholly done its office ; and thus the slices are made to fall into spirits of 

 wine, in which they are preserved for use. 



In some woods the pith shrinks so very fast, that it is extremely 

 difficult to keep it entire in slices that are thinner than 750 to an inch ; 

 to remove which imperfection an instrument of the nature above 

 described was made to shift its own screw at every revolution of the 

 handle, so that very little time was left to the pith to shrink, as a 

 hundred slices could easily be cut in a minute, and the pith was as 

 entire as the wood. This instrument had an index which, being set to 

 the numbers 500, 750, 1000, made it cut so many slices to an inch. It 

 performed extremely well, but was judged less fit for general use than 

 that which has already been described, it being more complex and liable 

 to disorder, as well as more difficult to manage. 



The cutting engine is an invention of the ingenious Mr. Cummings. 

 The two or three first were perfected under his own hand, and they are 

 now made for general use by Mr. Ramsden. 



Numbering Celloidin Sections.* — A. Yurisch gives an account of 

 his experiences with Suzuki's method of numbering serial celloidin 

 sections. This consists, briefly, in numbering the sections in order as 

 they are cut, by marking with Indian ink, so that although mixed 

 during subsequent manipulations, they may be mounted in the correct 

 order. The author finds that such Indian ink marks resist most of the 

 ordinary stains and reagents, and are still legible after sections have 

 been kept for several months. If the numbers are made too large the 

 excess of pigment may be deposited over the surface of the section in 

 small black indelible granules. On the whole, the method is to be 

 commended for its rapidity, simplicity, certainty, and cheapness. 



Fischek, Otto — TJber Ferienkwise fur Wissenschaftlche Mikroskopie. 



Zeitschr. wiss. Mikrosk., xxvii. (1910) pp. 94-114. 



(41 Staining- and Injecting-. 



Detection of Tubercle Bacilli in Milk and Fseces.f — E. H. R. 

 Harries recommends the following method. The smear is first stained 



* Zeitschr. -wiss. Mikrosk., xxvii. (1910) pp. 63-6. 

 t British Med. Journ. (1910) ii. p. 1295. 



