366 Chittenden and Painter— Casein and its 
cent. N and 1°55 per cent. S, for which they claim a_ position 
midway between serum-albumin and casein. It can be partially pre- 
cipitated from fresh milk at ordinary temperatures by the addition of 
acetic acid. Further, Lebelien* has proved the presence in milk of a 
globulin-like body, lacto-globulin, which can be precipitated by satu- 
rating the fluid remaining after removal of the casein with sodium 
chloride, with magnesium sulphate. The substance appears to be 
identical with paraglobulin, and thus this fact, just discovered, would 
seem to confirm Hammarsten’s theory as to the cause of the greater 
content of sulphur sometimes noticed in casein precipitated by hydro- 
chloric acid. 
Accepting then, Hammarsten’s views as correct, it is obvious that 
casein precipitated by acetic acid, if not a single body, must be com- 
posed of two bodies, more or less alike and both precipitable by 
dilute acids. In attempting to settle this point definitely, Hammars- 
ten has sought by analysis of a large number of preparations made 
under different conditions, to obtain data as to the exact composition 
of casein variously prepared. Naturally in this connection, consider- 
able attention was paid to the content of sulphur, since, Danilewsky 
and Radenhausen’s views being correct, variations in the content of 
sulphur would naturally be expected. If casein is a mixture of equal 
parts of caseoprotalbin and caseoalbumin with 1°13 per cent. and 
1°23 per cent. of sulphur, respectively, then casein itself would nat- 
urally contain 1°18 per cent. of sulphur; an amount somewhat higher 
than has been found heretofore. 
Recently, Dainlewsky+ has modified his views somewhat, and now 
considers casein, as before, to-be a mixture of two distinct bodies, 
but of nucleoalbumin with nucleoprotalbin instead of caseoalbumin 
and caseoprotalbin. As the reactions of these two bodies are appar- 
ently much the same as those given as characteristic of the caseo- 
bodies, this change of view appears to be mainly a change of name. 
Danilewsky still claims the correctness of the high content of sul- 
phur in casein and assumes that the variation in the results obtained 
by different workers is due simply to difference in the methods of 
determination, and that unquestionably pure casein contains over 1°0 
per cent. of sulphur. 
The content of sulphur in casein as determined 30-40 years ago by 
* Beitrag zur Kenntniss der Eiweisskorper der Kuhmilch, Jahresbericht fir Thier- 
chemie, 1885, p. 184. 
+See Zeitschrift fiir physiologische chemie, Band vii, p. 433. 
