GENERAL METHODS. I/ 



That collapsing may also be prevented by the use of 

 Schulze's settling-cylinder has already been noticed (cf. 21). 



2. The Transfer from Water to Canada Balsam Without the Use 



of Alcohol. 



(a) By Drying. 



23. A transfer from water to Canada balsam can be 

 accomplished without the use of alcohol by simply letting 

 the preparations dry in the air, then covering them with 

 xylol, which usually penetrates quite dry sections rapidly, 

 and then enclosing them in xylol-Canada balsam. Naturally 

 this method is applicable only to such preparations as suffer 

 no collapse from drying, especially to very thin microtome 

 sections. 



(6) With Aniline 



24. Since about 4$ of water is soluble in aniline, the latter 

 can be used for dehydration. The preparations are brought 

 directly from water into aniline, and may then be mounted 

 in Canada balsam. The aniline may be dehydrated by solid 

 potassium hydroxide (KHO), which is wholly insoluble in it 

 (cf. Suchanek I). 



(c) With Phenol (C,H,OH\ 



25. If sections are transferred from water to phenol which 

 has been melted by warming in a paraffine oven (cf. 47) or 

 by the addition of a little water, they are cleared in a short 

 time and sufficiently dehydrated to be transferred directly 

 to clove-oil or xylol. 



To prevent the collapsing of very delicate objects, the 

 method proposed by Klebahn (I, 419) may be used. The 

 fixed and stained objects are first placed in dilute glycerine, 

 which is allowed to concentrate in the air. Then phenol is 

 added, and clove-oil or creosote is gradually mixed with it, 

 when the objects may be directly transferred to Canada 

 balsam. Klebahn used these methods especially in the 

 study of the germinating spores of Desmids and carried on 



