zooLoar and botanTj miokoscopy, etc. 349 



with a set of emery wheels. He uses the palmar surface of the index 

 finger to press the section against the stone. " If a part of the ball 

 of the finger happens to come in contact with a finely polished and 

 well-moistened stone it will have but little if any effect upon the 

 epidermis." 



A tooth can thus be made ready to mount in thirty minutes after 

 its removal from the jaw, and the following advantages are claimed 

 for the method over the older ones, viz., " rapidity of preparation, and 

 thereby the specimen retains all of its original tenacity. It does not 

 curl up or become brittle, and thus one is enabled to get a larger and 

 more perfect specimen .... Perfect longitudinal sections of teeth have 

 been made in this way which were so thin that they would bend under 

 their own weight. This would be simply impossible in a tooth that 

 had become dry during the old process, as they become too brittle to 

 allow of such extreme reduction. The rapidity of reduction and 

 preparation readily admits of staining the protoplasm of bone sections 

 before retrogression sets in, and thereby their value is greatly 

 enhanced." 



Staining and Mounting Pollens and Smuts.* —= Eev. J. T. 

 Brownell gives the following as an original method : — 



" Place a blank slide on the turntable ; apply a small drop of the 

 staining fluid to the centre of the slide and place in it the requisite 

 amount of pollen and spread it evenly on the glass by placing the 

 sharp point of a teaser in the centre of the mass, and drawing it 

 gently to one side while the slide is rapidly revolving, washing away 

 the superfluous stain by dropping clean alcohol on the mass of pollen, 

 using for this purpose a sharp-pointed teaser; wipe away the out- 

 flowing fluid by the use of a small piece of clean cloth rolled up neatly 

 and applied to the outer edge of the waste fluid, gradually moving it 

 inward as the slide revolves, until only a small circle is left covered 

 with pollen. Allow a few moments for the alcohol to thoroughly 

 evaporate from this ; then apply a minute drop of spirits of tur- 

 pentine, so that the balsam may permeate the mass without inclosing 

 air-bubbles. Next apply the balsam, dropping it in a ring around the 

 pollen, and moving it up to the centre by placing the edge of a small 

 chisel held upright to the surface of the slide, and at an angle such 

 as to gather it (the balsam) together as the slide revolves. Now lay 

 on the cover-glass and settle it well into place, applying pressure 

 (with a tremulous motion of the hand) sufficient to bring all the 

 pollen-grains to a common plane, but yet so as to avoid crushing 

 them. Eemove the superfluous balsam, using the small chisel as 

 before, only setting it so as to throw the laalsam away from the cover 

 into an outer ring, which operation serves also to accurately centre 

 the cover-glass ; and lastly, using a wider chisel, take up this ring 

 of balsam, and the slide, furnished with a temporary label, is laid 

 away to cure." 



Practical suggestions are given as to collecting clean pollen, 

 preserving it for future use, avoiding mixing, teasers, chisels, &c. 



* Proc. Amer. Soe. Micr,, 7th Ann. Meeting, 1884, pp. 212-3. 



