MICROPHOTOGRAPHIC STUDY OF FAT GLOBULES OF MILK. 9

and number of fat globules in the milk of various Indian breeds of cows and
buffaloes, a similar classification could be made which would help the dairyman
in the choice of the breed of cow or buffalo most suitable for his requirement.

Early history of the detection of fat globules in milk.—The presence of fat globules
in milk was first reported by A. Van Leewenhocck in 1674. The manner in
which fat globules of milk are liberated by the mammary gland was explained
by Marshall [ 1922 ] in the form of three hypotheses which he put forth.

Bouchardat and Quevenne [ 1857 ] observed that the size of the fat globules
varied appreciably in the milk of different breeds, and indicated that the globules
in cow's milk varied from 10 to 2 microns in diameter.

Sturtevant [ 1873 ] reported the milk globules to appear as circles of unequal
diameters, and stated that these globules were enclosed in a thin membrane
or pellicle of extreme tenuity.

Babcock [ 1885 ] did not agree with Sturtevant that the fat globules were
enclosed in a thin membrane or pellicle. He compared the globules in milk
with artificial emulsions and concluded that they were not enclosed in a membrane
but were surrounded by a thin film of serum.

Methods employed for the study of size, shape and number of fat globules pre-
sent.—Different methods were used by different workers in the field for measuring
the fat globules of milk. The method used by Lamson [ 1888 ] was to dilute the
milk with three to four hundred parts of water, place a drop on a cover glass,
and invert over a cell on an ordinary microscope slide.

Collier [ 1891-92 ] used the method developed by Babcock, and studied the
variation in the size of fat globules in milk throughout the lactation period of
individual animals.

Various other workers have studied the variation in the size of the fat globules
in milk of individual animals of different breeds during their period of lactation,
a more recent publication in the field being that of H. Campbell [ 1932 ].

Results of the microphotographic study of the fat globules in samples of
milk of goats, cows, human beings and homogenised milk, have very recently
been published in an American journal by Apple [ 1935].

                                EXPERIMENTAL

Names of breeds studied.—The following is the list of breeds of Indian cows
and buffaloes which were considered for the purposes of this study. It represents
breeds of cattle of the purely draft type as well as milch type. The list is not
as complete as it should be and the omission of important breeds like the Sahiwal,

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