396 
Journal of Agricultural Research 
Vol. X XIV, No 
but in no case did both caprylic and capric acids agree with the average 
of the samples tested in Massachusetts. 
Of the insolubles, lauric acid was seemingly at least one of the smaller 
and m3^istic acid one of the larger ingredients, but only in a few cases 
were the results at all consistent. The range in palmitic acid was rather 
wide, but on excluding the higher percentages most of the remainder 
were between 15 and 25 per cent. 
In stearic-acid content there was again considerable divergence. The 
results may be divided into two groups from 1.08 to 3.35 per cent and 
from 5.54 to 15 per cent. Of the more recent workers Miss Smedley 
obtained a higher percentage than the others. The Massachusetts 
average herein reported on normal rations is somewhat higher than 
previously secured (9, p, log-iio) and may prove higher than subsequent 
figures from a greater number of cows will justify. 
Tl^^percentage of oleic acid varied from 25 to 46.49. A number of 
the fordgh butter fats had an oleic-acid content similar to those derived 
in Massachusetts from feeding com and soybean oils. This acid appears 
to respond the most readily to the influences of feed and advancement in 
lactation. 
The small quantity of di-hydroxy stearic acid reported in butter fat 
may arise from decomposition changes accompanying analytical proce¬ 
dure rather than as a natural occurrence. The weight of evidence does 
not support the contention that unsaturated acids higher than oleic are 
present in straight butter fat to any appreciable amount. 
GENERAL CONCLUSIONS 
(1) On normal rations the percentage of total fatty acids in the butter 
fat of the Holsteins was substantially the same as that of the Jerseys, 
but their neutralization number was somewhat lower; the free fatty 
acids and soluble fatty acids were also lower, while the percentage of 
insoluble fatty acids was higher and their neutralization number and 
glycerol lower. 
(2) The percentages of butyric and caprylic acids were lower in the 
Holsteins than in the Jerseys; caproic and capric acids higher; lauric and 
oleic acids higher; and myristic, palmitic, and stearic acids lower. 
(3) With advancing lactation the percentages of total fatty acids in¬ 
creased slightly in both breeds, while their neutralization numbers 
decreased; the soluble fatty acids decreased, while the insoluble fatty 
acids increased and their neutralization numbers and the glycerol de¬ 
creased. As a rule the changes were more pronounced in the Holsteins. 
(4) The addition of oils and fats to the normal rations increased the 
insoluble fatty acids, partly at the expense of the solubles and partly by 
increasing the total fatty acids, and in consequence depressed the glycerol 
content. 
(5) The neutralization numbers of the soluble, insoluble, and total 
fatty acids were decreased on feeding the peanut, com, and soybean oils, 
and that of the insoluble acids was increased by coconut fat. 
(6) Of the soluble acids, but);Tic fluctuated but maintained its per¬ 
centage, caproic acid decreased appreciably, and caprylic and capric 
acids decreased about 50 per cent in extreme cases. Of the insoluble 
acids, lauric and myristic acids increased when coconut fat was fed but 
decreased when unsaturated oils were fed. In the latter cases oleic acid 
increased greatly. 
