FEEDS AND FEEDIXG 993 



exercise an}- influence on the absolute freezing point of the blood and the 

 milk. For practical milk testing this fact is very important, as the lowering 

 of the freezing point of milk is often justified on the ground that it comes 

 from a diseased cow. 



The osmotic pressure of the milk, and in some cases of the blood, w^as 

 also studied in several cows with a diseased udder. Most of the animals 

 had streptococcal mastitis, the mastitis being of a tuberculotis nature in 

 2 cases only. Experiment proved that the milk was of very abnormal 

 composition. The diseased teats regularly gave an abnormal milk quite 

 different from the normal. 



The lactose had generally disappeared, and the content of ash and chlorine 

 corresponded to that of the blood serum. In spite of all these anomalies, 

 however, the freezing point of the milk was always normal, except in one 

 case where the animal was very ill owing to auto-intoxication. The blood 

 of the cows yielding this milk had a lower freezing point than that of the 

 blood of healthy animals, but it corresponded exactly to that of the milk. 

 These experiments therefore show that the worst forms of mastitis cannot 

 affect the osmotic concentration of the blood and milk in cows. 



The fact that as the mastitis develops the composition of the milk 

 resembles that of the blood serum more and more, has been explained by 

 the hypothesis that the process of secretion is gradually replaced by one 

 of filtration. It is a point in favour of this view that the freezing point 

 is not modified by the disease, because the filtered product (milk) has the 

 same freezing point as the blood of the same cow. 



From the fact that mastitis does not modify the equilibriiim between 

 the osmotic concentration of the blood and that of the milk, it is inferred 

 that milk from the diseasesd teats must have the same freezing point as 

 from the health}^ ones. Experiment proved the correctness of this view. 



By another series of experiments it was demonstrated that in cases 

 of mastitis the depression of the freezing point of milk remains unaltered so 

 long as the disease is not followed by general intoxication increasing the 

 osmotic concentration of the blood. This seems to contradict the results 

 obtained by the other investigators. The writer believes that the 

 depressions observed b}'' several investigators in the milk from a diseased 

 teat was due to detritus, etc, mixed with the milk in question. 



The cream has the same freezing point as the corresponding skim milk. 



The depressionof the freezing point, both in milk from healthy and from 

 diseased udders, is never less than 0.53 C. 



770 - Grain Screenings and Results of Feeding Experiments in Canada. — Dymond j . r. feeds 



Archibald Iv S., and Ivldorf 1'. C, in Ddminnni oi Cmuidu, Drpdiiment of Ai^riculture, and feeding 

 14 PP- ''^ tahk-s. Ottawa, 1915. 



Cereal growing has rapidly increased during the past few j^ears in the 

 prairie region of Canada. As a result of the system of continuous culti- 

 vation, the crops contain a noteworthy proportion of foreign .seed. In the 

 year ended 31st August 1913, the Inspection Service of the Cereals Commis- 

 sion of the Department of Commerce recorded the presence at the central 

 silos of more than 100 000 tons of screenings of wheat, oats, barley7and lin- 



