22 Mr. E. G. Young. On the Optical Rotatory 



Table VII. 



Date. 



Ph. 





[«]e. 



Date. 



Ph. 



OE. 



' We. 



April 20 ... 



4 9 



-8-37 



C 



-37 79 



April 20 ... 



4-9 



o 



-8 -37 



-37 -79 



„ 20 ... 



4-65 



-8 53 



-38 -48 



„ 20 ... 



5-4 



-8-09 



-36 -50 



21 ... 



4-65 



-8-58 



-38 '72 



„ 21 ... 



5 -4 



-8 -10 



-36-55 



„ 22 ... 



4-65 



-8-63 



-38-94 



„ 22 ... 



5-4 



-8-11 



-36 -59 



„ 23 ... 



4-3 



-8-74 



-39 "43 



„ 23 ... 



7-6 



-8-14 



-36 -73 



„ 26 ... 



4-3 



-8-72 



-39 "34 



„ 23 ... 



7-6 



-8 -15 



-36-78 



„ 30 ... 



4 3 



-8 -73 



-39 -39 



„ 25 ... 



7-6 



-8-14 



-36 -73 



„ 30 ... 



6-45 



-8-06 



-36 "37 



„ 26 ... 



7-6 



-8-20 



-37 -00 



May 2 



6 45 



-8-05 



-36 32 



„ 29 ... 



7-6 



-8-25 



-37 -23 



„ 4 ... 



7-1 



-8-61 



-38 -85 



» 30 ... 



7-6 



-8-25 



-37 -2:< 



„ 5 ... 



7-1 



-8 67 



-39 12 











Note on the Crystallisation of Ovalbumin. 



The role of acid in the process of crystallisation of albumin has received 

 some attention at the hands of a number of investigators since the procedure 

 was first carried out by Hopkins and Pinkus. These investigators found that 

 a 10 per cent, solution of acetic acid served admirably for the adjustment of 

 the solution so that crystals were deposited. Osborne recommended HC1 

 very shortly afterwards, while Krieger found H2SO4 to give the best results. 

 But as Hopkins pointed out in 1900 almost any moderately strong acid will 

 bring about crystallisation. In his extensive study of the emulsoid colloid 

 using crystalline ovalbumin as material, Sorensen (1917) employed N/5 H 2 S0 4 

 with additional water and (NH 4 ) 2 S04 solution. 



In the course of my experience I have had to prepare many small lots of 

 crystals and have employed several different acids of various strengths but 

 always adjusting the reaction finally to about the same optimum hydrogen 

 ion concentration. On several occasions I have found the method of Hopkins 

 to fail to yield crystals at the beginning, although the two possible causes of 

 failure which he mentions were excluded, viz., staleness of the eggs and 

 insufficient whipping. If, after a heavy amorphous precipitate has been 

 thrown down while standing after the usual adjustment, more acid be added, 

 crystals sometimes appear on further standing. These failures I attribute to 

 an increased alkalinity in the egg whites and inability to attain the proper 

 hydrogen ion concentration for crystallisation before the protein was 

 precipitated. 



On two occasions when the optimum conditions had been established for 

 crystallisation and a generous sowing of crystals added, a heavy precipitate 

 was obtained, which consisted entirely of round globules of various sizes — 

 the globuliths of the Hofmeister method of preparation. These globuliths 



