234 SUMMARY OF CURRENT RESEARCHES RELATING TO 



of the glass through the long axis of the groove, and fig. 50 a section 

 across the groove. 



When the objects are ready for imbedding, they are transferred to 

 the dish filled with melted paraffin and kept warm on the bath, by 

 carefully dropping them from a pipette into the groove. The bottom 

 of the dish is then rapidly cooled. When thoroughly hardened the 

 paraffin may be removed without difficulty, and it then has the form 

 seen in fig. 51. 



New Razor-holder and Adjustable Clamp for the Minot Micro- 

 tome.* — S. H. Gage advises the use of a razor with a straight edge and 

 back. This is fitted in a support which will allow nearly the whole 

 length of the cutting edge to be used, and which consists of a piece 

 of brass resting on the knife-support of the microtome. At right 

 angles to the base-piece on which rests the back of the razor, is a 

 vertical back-piece against which the side of the razor rests. This is 

 slightly narrower than the width of the razor-blade, and a notch is cut 

 out of the middle where the sections are made. A front-piece is made 

 like the back-piece, except that it is not fastened to the base-piece. 

 This is put against the front side of the razor and the clamping screws 

 of the regular knife-holder press against it. 



As the Minot holders for the paraffin blocks have but very slight 

 adjustment and are, moreover, somewhat expensive, short stove blocks 

 were recommended to meet the requirements of a large class. But as 

 these did not fit very often, an adjustable clamp was devised which will 

 receive bolts differing 1 or 2 mm. in diameter. The stem which 

 connects the clamp of the microtome has a long thread, and a solid 

 piece is screwed upon it. A loose piece like the first is then slipped 

 over the screw, and finally a thumb-nut is put upon the end to press 

 the loose piece against the fixed piece. Holes are bored in the clamp, 

 half the cylinder being in each. Either of these holes serves for the 

 paraffin block holder. Such a clamp surmounts the difficulties of 

 variations in the size of the stem of the paraffin holder. 



Dixon, H. H. — Sectioning without Imbedding. 



Hot. School T. C. Dublin, Aug. 1902. 



(4) Staining- and Injecting-. 



Staining Directions for Photomicrography.! — F. Crosbie remarks 

 that the stains selected in micrography often throw great difficulties in 

 the way of the photographer, rendering it impossible to obtain really 

 good negatives and necessitating the use of light-filters of great depth 

 of colour, with a corresponding diminution of actinic light-value and 

 an increase in the length of exposure. When it is known that a speci- 

 men is to be photographed the stain should be specially selected with 

 a view to this if possible. Hematoxylin is suitable for sections. 

 Gentian-violet gives the best results with bacteria. Fuchsin should be 

 avoided. In fact, it can be roughly stated that all stains on the blue or 

 violet side of the spectrum answer best, and stains belonging to the red 



* Trans. Amer. Micr. Soc., xxiii. (1902) pp. 259-61 (1 pi. and 7 figs.), 

 t Lancet, 1903, i. pp. 233-G (5 figs.). 



