1864. | Vornoxer on Milk, and Dairy Arrangements. 269 
cream which stood 48 hours was 1:0127 at 62° Fahr., and 1°0129 at 
62° Fahr. Rich cream, | find, has a lower specific gravity than thin 
cream mixed with a good deal of milk, such as the sample analysed 
under No. 1. 
No. 2 may be taken as representing the composition of cream of 
average richness. It then contains about one-fourth its weight of 
pure butter. 
These differences in the composition of cream fully explain the 
variable quantities of butter which are produced by a given bulk of 
cream. 
On an average, one quart of good cream yields from 13 to 15 ounces 
of commercial butter. When very rich in fat, it will yield rather 
more. Thus Mr. Horsfall states that a quart of cream yielded 1 Ib. of 
butter when the cows were at grass, and 22 to 24 ounces when they 
were housed and fed on rape-cake, bran, and other substances rich in 
oil. 
The portions of cream which first rise, are thin, but rich in fat ; 
this is due to the rupture of some of the oil globules during the milk- 
ing, and subsequent agitation to which milk is exposed; the light 
fatty contents thus liberated naturally rise quickly to the top of the 
vessel in which the milk is set. 
Good and poor milk differ mainly in the proportion of cream 
present ; the appearance may not be much varied, except in extreme 
cases; consequently, for the determination of the quality, more 
reliable tests are required than the mere inspection of the fluid; and 
as a preparatory step to the consideration of the evidences afforded by 
the specific gravity under various conditions, a few observations 
may be offered upon the microscopic examination of milk in health 
and disease.* 
Microscopic Examination of Milk in Health and Disease.—It must be 
some consolation to those who delight in miserable anticipations of 
dreadful mixtures in their daily food, to know that we possess a 
method of detecting, with absolute certainty, those combinations of 
“brains, chalk, and starch,” a haunting suspicion of which makes the 
morning and evening meal distasteful. 
Without positively asserting that such adulterations never exist, 
we may aver that we have never met with an instance. Foreign 
matters, of a nature unsavoury enough, and even unwholesome, we 
sometimes find, but they are the consequences of a diseased condition, 
or of an absence of common cleanliness. Such things as particles of 
dirt, from the milker’s hands or the cow’s udder, and cuticular scales 
from the same sources, are common enough. Globules of pus and 
blood discs are also found less frequently, but still oftener than we 
like to believe. It will not be thought that the microscope should be 
the companion to the breakfast-table : but in all cases where there is 
the least cause for suspicion, its revelations are infallible, and set at 
rest the doubt that is worse than certainty. 
» * The substance of the remarks on the microscopic appearance and the illustra- 
tions have been kindly contributed by my friend and former colleague, Professor 
G. T. Brown. 
