MILK. 
do not mention sugar of milk as a constituent, 
and in this respect agree with MM. Chevallier 
and Henry, who do not mention it in their 
analysis of the colostrum of the cow. 
Donné has observed a microscopic difference 
between the globules of the colostrum and those 
of milk. He states the colostrum globule to be 
made up of small granules united together, or 
enclosed in a transparent envelope. ‘They dis- 
appear in ether, and when the fluid is evapora- 
ted, small tufts of acicular crystals are observed. 
Donné traced these globules in milk secreted 
twenty days after parturition. M. Giiterbock 
has also observed these compound globules, and 
says he could detect the transparent membrane 
after the ether had dissolved the enclosed 
ules. M. Mandl has not been able to 
etect these compound globules, and believes 
_ them to be made up of agglomerated milk glo- 
bules. The following is the result of a com- 
tive analysis of colostrum and true milk by 
. Simon, 
Colostrum. Common milk. 
Casein .... 4 percent. 3.5 per cent. 
PAT S05 IT: a 5 AT: 5 
Putter 6.0. 5 5 2.3 
> 
I shall now proceed to the consideration of 
the milk of the human subject, which differs 
in some respects from that obtained from the 
cow; its general characters are, however, iden- 
tical. One of the principal differences to be 
observed consists in the caseous matter of 
human milk not being so universally preci- 
pitable by acids as that which exists in the 
secretion from the cow. Meggenhofen found 
but three out of fifteen specimens which he 
examined that could be precipitated by the hy- 
drochloric or acetic acids. Three specimens of 
human milk examined by myself were found 
not to be precipitable either by the muriatic, 
nitric, or sulphuric acids. Although human 
milk resists the coagulating power of the acids, 
it is, notwithstanding, easily precipitable by 
rennet; but the curd so formed is some time in 
collecting, owing to the minute size of the pre- 
_ Cipitating flocculi; thus there appears both a 
physical and chemical difference between the 
caseous matter from the human subject and 
that from the cow. The casein of human milk 
being incapable of forming insoluble combina- 
tions with the mineral acids, may be regarded 
as bearing chemically the same relation to the 
casein of cow’s milk that the albuminous matter 
of the chyle bears to that principle as it exists 
in the blood. The butyraceous matter of hu- 
man milk has been stated by some chemists to 
be too liquid to admit of the formation of 
butter by churning; this, however, has been 
proved incorrect by the experiments of Pleischl, © 
who succeeded in obtaining butter from the 
cream of human milk, which was similar in 
appearance to that from cow’s milk, and expe- 
riments into the nature of this form of butter 
have been made by Meggenhofen, who considers 
it as identical with that obtained from the cow. 
The specific gravity of human milk has been 
stated so low as from 1.020 to 1.025, but this is 
certainly far too low ; for out of six specimens 
_ which | examined the specific gravities varied 
361 
between 1.030 and 1.035. The proportion of 
solid matter contained in milk is, according to 
Meggenhofen, 11 to 12.5 per cent. and some- 
times more. I have had occasion to verify this 
result, having obtained 64.15 of solid matter 
from 500 grains of milk. The specific gravity 
of this specimen was, however, as high as 
1.0358. 
Human milk when fresh is either neutral 
or slightly alkaline. Its analysis, according to 
Meggenhofen, is as follows, being the results 
obtained from milk from three different sub- 
jects. 
No. 1. 
Alcoholic extractive, but- 
ter, lacticacid and lac- 
tates, chloride of sodi- 
um, traces of sugar of 
MES. Ais SOCAN 9.13.. 8.61,.17.12 
Aqueous extractive, sugar 
of milk, and salts .... 1.14.. 1.29.. 0.88 
Caseous matter (coagula- 
ted by rennet) ...... 2.41.. 1.47.. 2.88 
WaReP, Bis AScriene oils’. 87.25. .88.35. .78.93 
The specific gravity of the milk appears to 
increase as the woman continues suckling, this 
increase ceasing at some period which is as yet 
undetermined. Milk at three days after partu- 
rition I found of specific gravity 1.0310, at four 
days 1.0334, and at six weeks 1.0358. 
Payen has analysed three specimens of 
human milk with the following results :— 
Butter voles . 5.18... 5.16.. 
Caseous matter........ 0.24.. 
Residue of evaporated 
whey (containing the 
extractives, salts, and 
sugar of milk) ...... 7.86.. 7.62.. 7.93 
Water ........2.+---85.80. .86.00. .85.50 
Berzelius remarks upon these analysis, and 
says that a considerable portion of caseous 
matter remained in all probability in the whey, 
and was estimated in the residue obtained by 
evaporation. 
According to Meggenhofen the salts contained 
in milk amounted to from 0.5 to 1.25 parts in 
500 of the secretion. In an experiment made 
by myself, 500 grains of milk yielded 1.20 
grains of salts. 
Pfaff and Schwartz obtained 4.407 parts of 
ash from 1000 of milk, which they found to be 
composed as follows :— 
Phosphate of lime........+. 
Phosphate of magnesia...... 
Phosphate of iron.........- 
Phosphate of soda ........ 
Chloride of potassium ....., 
Soda from decomposed lactate 
5.20 
0.18... 0.25 
2.500 
0.500 
0.007 
0.400 
0.700 
0.300 
4.407 
Berzelius very naturally expresses surprise 
that no carbonate of lime, chloride of sodium, 
or alkaline sulphate, is mentioned in this ana- 
lysis, since casein always yields the earthy salt, 
and chloride of sodium is constantly present in 
animal matters which are intended for the nou- 
rishment of man. The absence of alkaline 
sulphate is quite inexplicable, as it is always a 
