42 THE VEGETABLE PROTEINS 



which has been produced by the action of acids, in the same way as 

 edestan is produced from edestin. 



Products similar to edestan are apparently formed from some of 

 the animal proteins with great ease, as, for example, from the myosins 

 of muscle tissue which rapidly become insoluble in neutral salt solution 

 during the development of acid which occurs in these tissues soon 

 after death. Whether other products than edestan are formed by the 

 action of acids on proteins before true " acid albumin " results has not 

 yet been determined ; but it is not improbable that such may occur. 



B. Denaturing by Alkalies. 



It has long been known that proteins undergo a change when 

 dissolved in solutions containing a moderate quantity of caustic alkali. 

 A product of this change which is known as " alkali albumin " or 

 "alkali albuminate" resembles in solubility the acid albumin which 

 results from proteins through the action of dilute acids. No satisfac- 

 tory study has ever been made of these two substances and little, 

 therefore, is known in respect to their relations to one another. 

 Whether one or more intermediate products are formed by the action 

 of alkali before the so-called alkali albumin results has not been 

 determined. 



No study of this action of alkali on vegetable proteins has been 

 made. Such scattered observations as are on record indicate that the 

 vegetable proteins are .less easily affected by alkalies than are the 

 animal proteins. Ritthausen's experience in extracting seed proteins 

 with dilute caustic alkali solutions showed that the precipitates produced 

 by neutralisation still retained, to a large extent, their solubility in 

 neutral saline solutions, from which it was clear that much of the 

 protein thus extracted had not been converted into alkali albumin. 



Chittenden and Osborne (72) found that zein was particularly re- 

 sistant to the action of alkali, for even after digesting with 2 per cent, 

 potassium hydrate solution at 40 for twenty-four hours, the zein still 

 retained its original solubility in alcohol and gave no evidence of the 

 formation of any " alkali albumin ". In this experiment the possibility, 

 however, is not excluded of the formation from zein of an alkali albumin 

 soluble in alcohol, for it may be that the zein had suffered a change 

 quite analogous to that which results in the formation of alkali albumin 

 without producing a substance whose solubility was like that of the 

 " alkali albumin " obtained from other proteins. 



Experience indicates that seed proteins are less easily altered by 

 small quantities of alkali than they are by acids, a fact which is contrary 



