2 1 6 BOTANICAL MICROTECHNIQUE. 



complished in many cases, as in Ricinus, by placing the 

 sections to be studied, for five minutes or longer, in absolute 

 alcohol. Less soluble fats may be extracted with ether or 

 with a mixture of equal parts ether and alcohol. Further 

 methods of study will depend upon the constituent of the 

 protein grain which it is chiefly desired to make visible ; 

 for there may be distinguished in them a proteid funda- 

 mental mass and various inclusions, protein crystalloids, 

 globoids, and crystals of calcium oxalate. These separate 

 constituents, which are not found simultaneously in all 

 protein grains, but yet are widely distributed, will be dis- 

 cussed in order. 



[But it may be well to give first two general methods 

 recommended by Krasser (III) for making permanent prep- 

 arations to show the grains and their inclusions in general. 



1. The sections are fixed with an alcoholic solution of 

 picric acid, rinsed with alcohol, stained in an alcoholic 

 eosin solution, " toned " with alcohol, cleared with clove-oil, 

 and mounted in balsam. The fundamental mass is stained 

 dark red, the crystalloid is yellow, and the globoid is colorless 

 or reddish. 



2. The sections are simultaneously fixed and stained in a 

 concentrated solution of nigrosin in an alcoholic picric-acid 

 solution. When the fundamental substance appears blue, 

 which may be determined by examining a section in abso- 

 lute alcohol with the microscope, the sections are washed in 

 alcohol, cleared quickly in clove-oil, and mounted in balsam. 

 This treatment stains the fundamental mass blue, the 

 crystalloid yellowish green, and leaves the globoid color- 

 less.] 



a. The Fundamental Mass. 



382. The fundamental mass of the protein grains, which 

 sometimes forms the bulk of the whole grain and some- 

 times only a thin envelope about the various inclusions, 

 consists of proteid substances and is well suited for the 

 study of the reactions of protein, detailed in 224 to 234. 



