78 



MEMOIRS OF THE NATIONAL ACADEMY OF vSCIENCES. 



These crystals were obtained by saturating with tlie globulin a 10 per cent sodium chloride solu- 

 tion heated to about 60° C, and allowing it to cool slowly in a large bath of warm water. 



After many trials with preparation 20 a portion of it was completely converted into perfectly- 

 formed octahedral crystals, which Prof S. L. Peufield, of Yale University, kindly examined and 

 pronounced to be isometric. These crystals were obtained by dissolving some of the substance in 

 cold distilled water and cautiously adding sodium chloride until a copious precipitate resulted. 

 On immersing the test tube in warm water the precipitate dissolved to a perfectly clear solution. 

 This solution was then allowed to cool slowly in a bath containing about four liters of water heated 

 to 60° O. After a day the deposit was examined under the microscope and found to consist 

 entirely of crystals. 



By saturating distilled water heated to 60° C. with preparation 20 and allowing the solution, 

 surrounded by a large volume of warm water, to cool slowly, an abundant deposit of octahedral 

 crystals was obtained, which were, however, not quite so perfectly developed as those just descrioed. 



VIII.— Peoteid derived feom the "Albuminate." 



(Preparations 21, 22, aud 23.) 



On treating 10 pounds of freshly ground oats with brine, precipitating the filtered solution by 

 saturating with ammonium sulphate, and extracting the precipitate thus obtained with brine, 

 it was found that a very large part of the globulin originally dissolved had been converted 

 into the so-called " albuminate." After washing this latter thoroughly with brine, to free it com- 

 pletely from the unchanged globulin, it was dissolved in a 1 per cent sodium carbonate solution. 

 About two-thirds of this solution was then treated with carbon dioxide for three hours, whereby 

 a heavy white precipitate settled out. This ijrecipitate was collected on a filter and allowed to 

 drain over night. The next morning it was found to have become transparent and gummy about 

 the edges. 



This precipitate was now completely soluble in salt solution and had all the properties of the 

 globulin (20) previously obtained from the hot sodium chloride extract. The entire precipitate 

 was then dissolved in one liter of brine and dialyzed for four days, during which time all but a 

 trace of the substance separated out. The thus precipitated proteid was seen under the micro- 

 scope to consist of spheroids of about one-tenth of a millimeter diameter or less, similar to those 

 obtained by cooling a warm solution of the globixlin. After filtering off, washing with alcohol, 

 ether, and absolute alcohol, 21 grams of air-dried material were obtained. This substance was 

 completely soluble in brine aud was precipitated therefrom by diluting with water, or by saturat- 

 iu"- with sodium chloride, or by adding minute quantities of hydrochloric, nitric, or acetic acid. In 

 the entire absence of salts, extremely small amounts of the just-named acids dissolved the proteid 

 instantly and completely, but the addition of a little sodium chloride precipitated it from this solu- 

 tion, the extent of the precipitation depending on the relative quantities of the acid and salt 

 present. The precipitation was complete when certain proportions of salt and acid were used. 

 Addition of strong soda lye to the solution of the proteid in dilute acid gave a heavy precipi- 

 tate, which dissolved but slowly in excess of soda, although the final mixture contained over 25 

 per cent of sodium hydrate. Addition of copper sulphate to this alkaline solution gave a violet 

 color. With Millon's reagent and with nitric acid, the usual proteid reactions were obtained. 

 Alcohol containing a minute amount of free acid dissolved the substance completely. Its compo- 

 sition was found to be as follows : 



Oat proteid derived from sodium carbonate solution of the ^'^ albuminates^ (21). 



