CHAPTER I. 



HISTORICAL REVIEW. 



IN 1747 Beccari (26) published in the Proceedings of the Bologna 

 Academy an account of his experiments with wheat flour, in which he 

 described the separation of the flour into two parts, one of which, he 

 says, was similar to "those things- that are extracted from vegetable 

 substances," and " the other was such that it did not seem possible to 

 extract it except from animal matter ". He states that he had already 

 communicated this fact to the Academy in 1728, but this communica- 

 tion appears to have never been published. After giving a detailed 

 description of the method by which he obtained this peculiar substance, 

 which we now know as wheat gluten, he describes at length the experi- 

 ments by which he compared its properties with products of animal 

 origin and contrasted its behaviour with that of other known substances 

 of vegetable origin. In making these comparisons he used destructive 

 distillation and pointed out that the distillates from vegetable materials 

 were acid, while those from the wheat gluten were alkaline like the 

 distillates from animal substances^ A comparison was also made between 

 the products of putrefaction of gluten with those yielded by animal 

 and vegetable matter under similar conditions. Attempts to obtain a 

 product like gluten from beans, barley and other seeds failed, and wheat 

 appeared to be the only plant whose seeds contained anything re- 

 sembling substances of animal origin. 



Kessel-Meyer (187) in 1759 was the next to call attention to gluten, 

 and gave a brief description of its preparation and of experiments to 

 determine the action of various solvents upon it. 



Rouelle (440) in 1773 announced that the glutinous matter, which 

 up to that time was known to exist only in the seeds of wheat, was 

 present also in other parts of various plants. This he considered to 

 be the nutritive substance from which the caseous part of milk was 

 derived. He stated that it was insoluble in water and gave rise to the 

 same products as the gluten of flour, and also that it can be changed 

 into a body having the same odour as cheese, as Kessel-Meyer had found 

 to be the case with wheat gluten. 



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