[hil REPORTS ON THE STATE OF SCIENCE.—1918. 
Harden and Lane-Claypon, Journal of Hygiene, 12, 143 (1912). 
Kooper, Milch. Centralb.. "7, 411, 264 (1911). 
Koning, Milch. Centralb., 3, 41. 53 (1907). 
Lam, Maly’s Tierch., 36, 232 (1906). 
Neumann-Wender, Oester7. Chem. Zeitung, 6, 1 (1903). 
Raudnitz, Ergebnisse der Physiologie (193) 2, pt. 1. p. 274. 
Rullmann, Arch. f. Hyg., ‘73, 81 (1911). : 
Sarthou, (. Rendus., 110, 119 (1910). 
Schroeter, Centralb. f. Bakt., ii. 32, 181 (1911). 
Seligmann, Zit. f. Hyg., 59, 97 (1905) and 58, 1 (1908). 
Smidt, Arch. f. Hyg., 58, 313 (1908). 
Spindler, Biochem. Zeit., 30, 384 (1911). 
Fora detailed study of the enzymes of milk cf. Lane-Claypon, 
‘Reports to the Local Government Board on Public Health and 
Medical Subjects’ (New Series), No. 76 (1913). 
(d) Amylase. 
This enzyme is only present in small amount, e.g. Lane-Claypon 
found that 10cc. of cow’s milk at 37°C hydrolysed about ‘001 to -002 
grm. of starch in three hours. . The starch is converted to dextrins. 
Koning found the amylase activity of milk to be destroyed on 
heating to 68° C. for 45 minutes. 
MARGARINE. 
Margarine technology presents many questions of great interest 
to the Colloid Chemist, and offers a wide field of research in pure 
physical chemistry. 
Margarine is a substitute for Butter, certain animal and vegetable 
oils and fats replacing the familiar butter fat. Thus stearine, oleo, 
lard, cocoanut oil, palm kernel oil, cottonseed oil, and arachis, kapok, 
maize, and wheat oils are all in present use. The oils and fats are 
liquefied together in certain proportions, depending on the quality of 
the margarine required, and then churned with soured milk to form 
an emulsion. This emulsion is rapidly cooled, either by means of a 
spray of iced water under pressure, or by flowing on to well-cooled 
revolving drums. The product in each case is then worked up in 
drums or rollers to the required buttery textvre and consistency. 
For an account of modern Margarine Technology, cf. Clayton, 
J.8.C.1., 36, 1205-1209 (1917). 
In the manufacture of margarine, the process of emulsification is 
of first importance. “The object of churning is to imitate the 
emulsion found in cream and milk, where the fat globules have 
diameters ranging from 0:01 m.m. to 0:0016 m.m. and remain as 
discrete particles. The general theory of emulsification indicates 
that with two immiscible or only partly miscible liquids, two types 
of emulsion are possible, each constituent being in turn the disperse 
and then the continuous phase. For concentrated sclutions a third 
(emulsifying) agent is required. Where cil is to be the internal or 
disperse phase, the. emulsifying agent should be capable of lowering 
the surface tension of the external or continuous medium, and should 
be viscous, as is glycerin, or an emulsoid, like gelatin. If oil be 
dispersed in water, a stable emulsion can be made, the stability 
depending on the minuteness of the oil drops, this in turn being a 
result of the efficiency of the emulsifying apparatus. If, however, 
