222 EXPERIMENT STATION RECORD. 



obtained by the repeated digestion, there was still a small residue, con- 

 sisting mostly of ash, but containing some organic matter. The ammo- 

 nia extract containing the incrusting substances was evaporated. The 

 sum of the cellulose, the ammonia extract, and the residue was very 

 nearly equal to the amount of substance taken. The cellulose dis- 

 solved out in the above process contained varying quantities of 

 pentosan, according to the nature of the material taken. 



The ammonia extract from wood and cork was dark brown, gave an 

 odor of vanilla on evaporation, and the dried residue was insoluble in 

 water but soluble in ammonia and reprecipitated by acid. It is believed 

 to belong with the humus acids and was not further studied. The 

 lignin from less lignified materials was quite different. Here the extrac- 

 tion was more rapid and the cellulose residue was greater. In case 

 of wheat bran silicic acid was recognized as the principal incrusting 

 substance. 



Aside from the humus acids another substance was regularly found, 

 the occurrence of which has been previouslynoted by the author. 



It has thus far been obtained only in amorphous form. Its ele- 

 mentary composition and general characteristics are given and further 

 communications are promised. 



The proteids of cows' milk, K. Storch (Monatshefte Chem., 18 

 {1897), pp. 214-281; Chem. Ztg., 21 (1897), No. 12, pp. 419, 420).— The 

 author reports studies on this subject, using sodium sulphate, magne- 

 sium sulphate, and common salt as precipitants. The fat was removed 

 from milk by skimming after standing 24 hours, or by means of a sepa- 

 rator. The skim milk mixed with 3 times its volume of a saturated 

 solution of sodium sulphate and a little eg;g albumin, and heated to 

 100° is curdled. If the filtrate is neutralized with a saturated solution 

 of sodium sulphate containing a very little acetic acid, and is then mixed 

 with an excess of solid sodium sulphate, a precipitate a is obtained. 

 The filtrate from this yields another precipitate b with strong acetic 

 acid ; and the filtrate from b contains no proteids. If, on the other hand, 

 the skim milk is at once saturated with solid sodium phosphate without 

 previous coagulation , a separates out as before, and the filtrate yields with 

 acetic acid the precipitate b, but the filtrate from b is found to still con- 

 tain a proteid which is believed to be the lactalbumin found by other 

 authors. In the first method the lactalbumin (and lactoglobulin) is pre- 

 cipitated in the preliminary coagulation. The precipitates a and b both 

 contain phosphorus. The substance is combined w.ith calcium, is solu- 

 ble in water, and is completely curdled by rennet; while b contains no 

 lime, is insoluble in water, and is only slightly affected by rennet. The 

 precipitates a and b can also be obtained with either magnesium sul- 

 phate or common salt. The amount of a obtained from 20 cc. of milk 

 ranged from 0.47 to 0.5G gm., and of b from 0.05 to 0.08 gm. Acetic acid 

 pr-ecipitates the larger part of a and b from diluted milk as caseinogen; 

 the filtrate yields very little of a and b upon treatment with the above 

 salts 



