929 Tur Microscopsé. 
croscopic Examination of Butter, and its Adulterations.” The fol- 
lowing is a brief resumé of the points made : 
He analyzed Dr. Taylor’s method, now well known, for the 
examination of butter and fats, and divided it into three parts, viz: 
the detection of foreign bodies other than fat; the examination of 
the commercial fat by polarized light without further treatment, 
and lastly, the examination of the crystalline nature of butter and 
other fats, after submitting them to heat according to his well- 
known directions. 
The first part of the method was, in the opinion of the speaker, 
the only one which gave any promise of true value, yet it was the 
one upon which its author (Dr. Taylor) laid least stress and con- 
sidered of least value. By this method tissues, and other foreign 
matters, that would suggest the origin of a product and thus dis- 
tinguish it from pure butter, might easily be discerned and recog- 
nized. As to the second part of Dr. Taylor’s process, while tests of 
unprepared fats made with polarized light, as directed by the doctor, 
apparently confirmed his statements, (viz: that the normal butter, 
over the green selenite-plate, displays an even green color, while 
lard and other fats display prismatic colors due to the crystalliza- 
tions present therein,) the fact is that the confirmation is only ap- 
parent—and the conclusions drawn from it by Dr. Taylor are op- 
posed to all law and reason. The difference in the behavior of the 
butter and the other fats is due not, to any inherent property in 
either of them, but to the difference of the conditions in the treat- 
ment which these fats had undergone prior to reaching the experi- 
menter’s (Dr. Taylor’s) hands; in other words, that, had the butter 
been subjected to the prior treatment, which the other fats had un- 
dergone, it too would have displayed prismatic colors. Dr. Weber 
cited a number of experiments made by him to prove this point, 
and finally gave, as an explanation of the fact that the fresh, unma- 
nipulated butter had shown an even field, the statement that the 
natural crystals of such butter were exceedingly minute, and hence 
produced an effect on the polarized rays so obscure as to be almost 
or quite inappreciable. By melting any of the other fats which had 
produced prismatic effects, and suddenly cooling them so as to 
break up their crystals into forms as minute as those of butter, the 
very same results were obtained. 
A most important deduction made from these experiments is 
