SOME VEGETABLE PROTEIDS. 139 



IV. BBAZIL-NUT GLOBULIN. 

 Preparation and Composition. 



The globulin obtained from the Brazil nut was chosen for 

 investigation because it differs somewhat in its chemical 

 composition and reactions from the two previously studied. 

 These differences are regarded by Osborne as sufficient to 

 warrant its being classed as a distinct proteid body.* The 

 preparations used in this investigation were obtained by the 

 following methods: 



A fine white meal was prepared from the meat of the Brazil 

 nut by grating it, extracting the oil with benzine, and then 

 sifting it through a fine sieve. Two methods were employed 

 to obtain the globulin. By the first it was extracted from 

 the prepared meal with distilled water at 60 C. and then 

 precipitated by cooling. This precipitate was collected on a 

 filter and washed successively with dilute alcohol, absolute 

 alcohol, and ether, and dried, after the evaporation of the 

 ether, over sulphuric acid. By the second method the globu- 

 lin was extracted from the prepared meal with a 10 per cent 

 sodium-chloride solution at 20 C. and the extract submitted 

 to dialysis for a few days. The resulting precipitate was 

 collected on a filter and washed and dried in the same manner 

 as that obtained by cooling from the water extract. The 

 second method gave the largest yield of globulin, and was on 

 the whole found to be the more satisfactory, although the 

 preparation was not as well crystallized as that from the 

 water extract. In neither case were the globulin crystals as 

 perfect as those obtained from the flax-seed and hemp-seed. 

 The Brazil-nut globulin crystals varied in form from a thin 

 hexagonal plate, through more or less rounded forms, to a 

 perfect spheroid. The most common form, and in fact the 

 only one found in the globulin precipitated by cooling, was a 

 thick hexagonal plate with every other angle rounded off. 

 In bulk the crystallized globulin appeared as a very fine, pure 

 white powder. 



* American Chemical Journal, vol. xiv, p. 687.^ 



