516 EXPERIMENT STATION RECORD. 



difference in composition of these preparations " barely exceeds the 

 usual errors of analysis, although several determinations of each ele- 

 ment in the different fractions indicate that these differences are not 

 due to analytical errors." 



In order to study the effect of minute quantities of acid on these 

 fractions of globulin 2 gm. of each were treated with 20 cc. of 0.05 per 

 cent acetic acid, which caused no noticeable solution of the proteids. 

 Two grams of salt was added to each, whereby A was largely, B partly, 

 and G only slightly, dissolved. Heated to 50° A gave a clear solution, 

 B a nearly clear solution, and C dissolved only partly and precipitated 

 on cooling to 20°. A solution of A was prepared in the same manner, 

 omitting the acid. It was found " that a quantity of acid too small to 

 be detected with litmus or by analysis causes changes in the fractions 

 soluble in saturated salt solution (A) whereby products result having 

 the same general properties as those exhibited by the fractions B and C" 



The experiments were repeated and extended, using crystallized 

 edestin from hemp seed. 



"Here again we see that the addition of a quantity of acid, too small to detect 

 after the solution has been made, brings about changes similar to those naturally 

 occurring in the seeds and extracts of the castor bean and sunflower and to those 

 following the addition of acid to that part of the globulin of the castor bean which 

 is soluble in saturated salt solutions. 



"Whether such changes occur only through the influence of acids is a question 

 not settled, and regarding winch some doubt is raised by the fact that preparations 

 of crystallized edestin which were originally soluble in 10 per cent sodium chlorid 

 solution, with the exception of a small quantity of ' albuminate' and yielded solutions 

 which gave ouly traces of precipitates on saturating with sodium chlorid, were 

 found, after keeping dry and in eork-stopped bottles 2 and 4 years, to have become 

 largely insoluble in cold salt solution and to yield solutions which were nearly com- 

 pletely precipitated by saturating with salt. The insoluble portion dissolved nearly 

 completely in 10 per cent brine at 60° to a solution precipitated somewhat by cooling 

 to 20° and abundantly at lower temperatures, copiously precipitated by dilution with 

 an equal volume of water, and almost completely precipitated by saturating with 

 sodium chlorid. It is not at all impossible that this change, too, may have been 

 caused by acid, for these preparations stood during several years in the laboratory, 

 the air of which at times contained some acid vapors.*' 



It is believed that this change of the globulin to a condition in which 

 it is precipitated by salt is an intermediate step toward the formation 

 of the insoluble form, the so-called u albuminate" of Weil. 



The proteids of the sunflower seed, T. B. Osborne and G. F. 

 Campbell {Connecticut State Sta. Bpt. 1896, pp. 374-379). — Crushed 

 sunflower seed from which a large part of the woody shells had been 

 removed was ground under benzin, and after freeing from oil was air 

 dried and treated with a 10 per cent brine. From the extract a con- 

 siderable quantity of proteid could be separated by dilution, by 

 dialysis, or by saturation with salt. 



Preparations were made and analyzed, indicating the principal pro- 

 teid of the sunflower seed to be a globulin, but the preparations were 



