242 THE MICROSCOPE. [December, 



starches, common drugs and their adulterations. Plant beans, 

 corn, and other seeds, and study the development of roots and 

 stems. Practise free-hand sectioning — that is, holding the mate- 

 rial in the fingers, or, if too small, imbedded in a piece of carrot, 

 and thin slices cut with a razor flooded with water or alcohol ; 

 this very useful accomplishment will enable one to make speedy 

 examinations of material and so determine its value for more 

 careful investigation, and surprisingly handsome sections can be 

 cut by a practised hand. The writer has many such hand-cut 

 sections, originally intended for temporary study, but found 

 worthy of permanent preservation. 



MEANS 



Gulland's Method of Fixing Paraffin Sections to the 

 Slide. — After pointing out the difficulties arising from the use of 

 the albumen fixative, the author offers the following method : 



The tissue is imbedded in the usual manner. In trimming the 

 block for sectioning, care must be taken to see that the surface 

 meeting the razor is exactly parallel to the opposite surface ; these 

 surfaces are then coated with soft paraffin, and when this has 

 hardened are again trimmed square. The reason for this special 

 care is that any curve in the ribbon produced by neglect of this 

 precaution is accentuated by the later flattening of the sections. 

 When all the sections required have been cut, the ribbon is 

 divided into lengths corresponding to that of the cover-glass in 

 use. 



A flat glass dish filled with warm water is now provided ; the 

 temperature should never be high enough to melt the soft paraffin 

 holding the sections together. Short of this, however, the warmer 

 the water the more rapidly and completely are the sections 

 flattened. 



The ribbons are seized at one end with forceps while the other 

 end is gently lowered upon the surface of the warm water ; as 

 the sections flatten out they will move along the surface of the 

 water ; when the flattening is complete, the slide, carefully cleaned, 

 is immersed in the water. The ribbon is floated into its position 

 with a stiff brush ; this process is repeated until the slide is full, 

 when it is set up on end until the water is thoroughly drained 

 off. The slide is then transferred to the top of the imbedding 

 oven, where the temperature is a little under 50° C, and where, 

 consequently, the paraffin of the sections is not melted, though 



