Recent Agricultural Puhlications. 
827 
of the analysis of more than 1,000 butters from different parts 
of the world, and, in addition, those of a large number of 
animal and vegetable fats, are given in tables. In dealing with the 
variations in composition which are found in natural butters, the 
author quotes the observations of various investigators on the effect 
produced on the composition of butter by the method of feeding 
cows, whether on pasture or in stall, the nature of the food, the 
breed and age of the cow, and the length of time that has elapsed 
since parturition ; also season, locality, and the mode of churning and 
packing the butter. 
The author criticises in detail the analytical values of the various 
processes, and of the interpretations placed on the results obtained 
by them, and he gives his opinion that no chemist or body of 
chemists is authorised in adopting, as a base for calculations, 
fixed limits for the amounts of insoluble fatty acids, volatile acids, 
<fec., which shall be present in natural butter. In Volume II., the 
author describes his own researches and gives a new general method 
of his own devising for the analysis of butter and other fats. It 
would be impossible, without entering into technical details, to 
discuss this new method of analysis ; but it may merely be pointed 
out that the process has for its object the separation and estimation 
of the several groups of acids of butter-fat, as determined by the 
solubility, in different reagents, of the baryta salts of these acids. 
Inasmuch as only half a gramme of butter-fat is taken for this 
complex series of separations, the experimental error is likely to be 
sufficiently great to seriously interfere with the accuracy of the 
process. In chapter v. of this volume, M. Zune discusses the 
question of the “ limits ” within which it is possible to detect the 
admixture of margarine with pure butter. He concludes that in spite 
of all determinations — physical and chemical — the interpretation 
of the results will often present serious difficulties on account of the 
great variability in the composition of natural butter, and he 
declares, with strong emphasis, that it is impossible to detect with 
certainty the admixture of 10 per cent, of pure margarine witli 
natural butter. Indeed, by careful selection it would be possible to 
mix a much larger proportion of margarine with butter without any 
certainty of detection. 
After giving a long list of chemical and physical determinations, 
which he considers as essential in the ascertainment of the purity 
of a butter, M. Zune suggests, as a check upon adulteration, that the 
butter derived from different countries should have definite nume- 
rical values fixed, according to each month of the year, for the 
various constituents. The fixing of “ standards,” however, appears 
to be very undesirable. The result would be to perpetuate whole- 
sale and systematic fraud, and to play into the hands of those who 
have made the sophistication of butter a scientific study. 
Upon the important question of the detection of the admixture 
of margarine with butter, M. Zune has given an able and, on the 
whole, a fair criticism of the merits of the various methods of 
analysis adopted for this end. The great difficulty undoubtedly lies 
