300 SECTIONAL TRANSACTIONS.—B. 
from the bulked fresh milk of a herd. On that account it would be difficult 
to say whether milk has been watered if values in the neighbourhood of 
— 050° C. were obtained. The author has found the form of the freezing 
point curve for moderately concentrated aqueous solutions of non-electro- 
lytes. The results obtained from the use of this curve have been applied 
in order to get the best approximation to the true freezing point of milk. 
Dr. W. L. Davies.—Chemical composition of abnormal milk (10.40). 
Milk may be defined as abnormal when its contents of fat, casein and/or 
lactose fall outside certain expected ranges or when it shows abnormality 
of behaviour towards rennin or heat, or abnormal buffer value. 
The following table 1 gives the expected levels of composition of normal 
cow’s milk and the composition of milk which must be considered abnormal, 
for comparison :— 
Values in percentage of weight of the fresh milk. 
Normal Milk. Abnormal Milk. 
——ao_un———~. 
Range. Average. 
Fat, per cent. . : 2°8-5°5 3°6 Usually low. 
Lactose, percent. . 4°0-5°2 4°9 <4°2 
Chlorine (Cl), per cent. 0°045-0°150 0°'095 >0°I50 
Total nitrogen . .  0°46-0°54 0°50 Variable. 
Percentage of total nitrogen. : 
Protein nitrogen : 92-96 94 fHigh in retained milk, 
| otherwise low (85-91). 
Casein ss , 74-81 76 Less than 74. 
Albumin _,, ; II-I3 12 { Both or either, ‘high and 
Globulin _,, : 5-7 6 \ variable. 
Tes {Low in retained milk, 
Non-protein nitrogen 5-7 6 | otherwise high (9-15). 
On the assumption that abnormal milk = true milk fraction (containing 
casein N = 76 per cent. of total nitrogen) + diluting fraction, the nitrogen 
distribution and chlorine content of the diluting fraction has been calculated.” 
The fraction closely approaches blood or lymph serum or cedema fluid in 
composition ; this points to abnormality as being due to inefficiency in the 
secretory process in the elaboration of casein from the nitrogenous com- 
pounds of the blood and in secreting lactose. 
Abnormality in buffer value in the acid range, in the balance of acidic 
and basic constituents, in the distribution of ionic and non-ionic metallic 
radicles (Ca), in the amounts of the various forms of casein present and in 
the amount of heat-coagulable protein, is reflected by abnormality in rennet 
action, in ‘ curd tension ’ and in heat stability at temperatures above 100° C. 
Discussion (11.0). 
Dr. K. LinperstrgM-Lanc.—Some chemical and physical properties 
of casein (11.20). 
Casein (caseinogen), the phosphor protein in milk, is a mixture of two or 
more substances. By treatment with acid alcohol it may be divided into 
1 Davies, J. Dairy Res., 1933, 4, 142. 2 Ibid., 1933, 4, 273- 
