378 
Report of the Chemist of the 
Reichert's method has been quite generally adopted by chemists for 
the detection of adulteration, and for this purpose is probably the 
most satisfactory that has been proposed. It appears, however, from 
figures given above, and others which might be cited, that the lower 
limit adopted is too high. Certain it is that some pure butters, and 
especially those from single cows, may fall considerably below 12.5 c. c. 
2. Iodine Number. 
Oleic is the only fatty acid found in the glycerides of butter fat 
which has the property of absorbing iodine. Each molecule of this 
acid absorbs one molecule of iodine, so that the per cent of iodine 
absorbed is directly proportional to the per cent of olein present. 
The variation of this number, especially in the butters from single 
cows, is very great, showing the per cent of olein to vary in these 
butters from 27.7 to 52.1. There is also a very decided difference 
between .the Holstein and other breeds, the average for the Holstein 
being olein 46.19, that for the other cows tested being 35.4 per cent. 
The average for 26 samples of butter, including that from single cows 
and dairies, has been olein 41.5 per cent. This high per cent of 
olein in Holstein butter will account for its softness as compared with 
Jersey butter. 
The wide range in the iodine number shows olein without doubt to 
be the most variable constituent of butter. This, in connection with 
the variation due to breed, is sufficient to render the test useless for 
the detection of adulterations. It is, however, of value as an indication 
of the composition of butter. 
3. Saturation Equivalent — Koettstorfer's Method. 
The volatile fatty acids of butter have a much lower molecular 
weight than stearic, oleic or palmitic; consequently butter requires 
more alkali for saponification than fats which contain only the latter 
acids. Thus lard, tallow and the oils used as adulterants, all require 
less than 200 milligrams of potassium hydrate for each gram of fat, 
while butter requires from 220 - 232 milligrams. 
By comparing the figures for the above butters we find that the 
Holstein butters quite uniformly require less potassium hydrate for 
saponification than do the Jersey butters. This, taken by itself, indi- 
cates that the Jersey butters contain a larger proportion of volatile 
fatty acids than the Holstein. Reichert's test, however, does not con- 
firm this. It seems, therefore, that the insoluble fatty acids of Hol- 
stein butter must consist on the average of fatty acids of higher molec- 
ular weight than Jersey butter. In other words, if the insoluble 
