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fairly permanent increase of 0.2 to 0.3 per cent of fat in the milk. 
On the other hand maize and linseed oils, when given as a regular 
diet, while causing a marked increase in the fat at first, seemed to 
lower the percentage of fat in the later stages of the experiment. 
Essentially similar results have been obtained by V. Henriques and 
Hansen (51). Sebelien (52) has found that the effect of feeding 
whale meal was to increase the yield of milk 6 per cent during the 
period when it was given. There was no after effect. The absolute 
amount of fat was increased during the first period of whale-meal 
feeding, but sank during the last period to the amount produced in 
the preliminary period. The percentage of fat was not altered by the 
whale meal when this was given as additional food, but was lowered 
when an extra quantity of it was given. Wing (53) found that the 
addition of fat to the fodder neither increased the quantity of milk 
nor the amount of fat which it contained. Morgen, Beger, Finger- 
ling, Doll, Hancke, Sieglin, and Zielstorff (54) working together, have 
shown as the result of an extensive series of investigations on the 
effect of foods and food fat on the production of milk and milk fat in 
sheep and goats that food almost free from fat maintained the ani- 
mals in healthy condition and increased the live weight of the animal, 
but that such foods were unsuitable for milk production. Food fat 
in small quantities, 0.5 to 1 gram weight per kilo of the animal was 
found to promote the production of milk fat. They proved further 
that so far as their effect on milk production and the increase of fat in 
milk is concerned, stimulants are only desirable in certain cases. 
These investigations have been further extended by these observers 
working together or alone. For example, Morgen, Beger, and Fin- 
gerling (55), as the result of studies extending over six years, have 
reached the conclusion that of all foods, fat alone exerts a specific 
action on the production of milk fat, proteids' and carbohydrates 
exerting no such action, and that within certain limits fat is the most 
suitable of all foods for milk-fat production, and in this same con- 
nection, Fingerling (56) has shown that the replacement of food 
deficient in fat (barley meal) by one containing more fat (rice meal) 
increased both the absolute amount and the percentage of fat in the 
milk. From a study of the influence of stimulants on the consump- 
tion and digestibility of food and the secretion of milk he (57) has also 
arrived at the conclusion that when added to foods entirely free from 
stimulants the effect of the stimulant is to increase the consumption 
of food and the yield of milk and milk constituents. When how- 
ever stimulants are added to foodstuffs already containing such sub- 
stances they are without effect on the yield of milk. He concluded 
therefore that they are of use only in special cases, as, for example, 
when cattle are fed with hay. In such cases the addition of such 
