M I 
woman's milk with a view to determine this point. He 
made ufe of ardent fpirits, all the different acids, infufions 
of infants’ ftomachs, and procured the milk of a great 
many different women ; but in no inftance, excepting one 
or two, did he perceive any thing like curd. This took 
place -in confequence of a fpontaneous acefcency ; and 
only a fmnll quantity of fort flaky matter was formed, 
which floated in the ferum. This moreover he looked 
upon to be a morbid appearance. 
The general opinion that women’s milk is coagulable 
has arifen from a Angle circumftance, viz. that infants 
frequently vomit the milk they fuck in a ftate of apparent 
coagulation. This greatly perplexed Dr. Young; who, 
after having tried in vain to coagulate human milk artifi¬ 
cially, concluded that the procefs took place fpontaneoufly 
in the itomach ; and that it would always do fo if the 
milk were allowed to remain in a degree of heat equal to 
about 96 degrees of Fahrenheit. Mr. Clarke took equal 
quantities of three different kinds of milk, and put them, 
into bottles flightly corked, and thefe bottles into water, 
the temperature of which was kept up, by a fpirit-of-wine 
lamp, as near as poflible to 96® of Fahrenheit; but, after 
.frequently examining each-bottle during the courfe of 
the experiment, at the expiration of feveral hours there 
was not the fmallefl tendency towards coagulation to be 
perceived in any of them ; the cream was only thrown to 
the furface in a thick and adhefive form, and entirely le- 
parated from the fluid below, which had fomething of a 
grey and wheyifh appearance. As the matter vomited by 
infants is fometimes more adhefive than we can fuppofe 
cream to be, Mr. Clarke fuppofed that the curd might be 
fo entangled with the cream, as to be with difficulty fepa- 
rated from it; but, having collefted a quantity of; rich 
cream from the milk of different women, he repeated the 
experiment with precifely the fame event, not being able 
in any one inftance to produce the fmallefl quantity of 
curd. To determine, however, what effedls might be 
produced upon milk by the ftomach of an infant, Mr. 
Clarke made the following experiment: Having taken 
out the ftomach of a fcetus which had been deprived of 
life by the ufe of inftruments, he infufed it in a fmall 
quantity of hot-water, lb as to make a ftrong infufion. 
He added a tea-fpoonful of this infufion to equal quan¬ 
tities of cow’s and human milk; the confequence of 
which was, that the cow’s milk was firmly coagulated in 
a fhort time, but the human milk was not altered in the 
leaft ; neither was the leaft coagulation produced by add¬ 
ing a fecond and third fpoonful to the human milk. 
“ Upon the whole, then, (fays Mr. Clarke,) I am per- 
fuaded it will be found, that human milk, in an healthy 
ftate, contains little or no curd, and that the general opi¬ 
nion of its nature and properties is founded upon fallaci¬ 
ous analogy and fuperficial obfervations made on the mat¬ 
ter vomited by infants. We may prefume, that the cream 
of women’s milk, by its inferior ipecific gravity, will fwim 
on the lurface of the contents of the ftomach ; and, being 
of an oily nature, that it will be of more difficult digeftion 
than any other conftituent part of milk. When an in¬ 
fant then fucks very plentifully, fo as to over-diftend the 
ftomach, or labours under any weaknefs in the powers of 
digeftion, it cannot appear unreafonable to fuppofe, that 
the cream fliall be firft rejected by vomiting. Analogous 
to this, we know that adults affedted with dyfpeplia often 
bring up grealy fluids from the ftomach by eradiation, and 
this efpecially alter eating fat meat. We have, in fome 
inflances, known this to blaze, when thrown into the fire, 
like fpirit of wine or oil.” Our author derives a confirma¬ 
tion of his opinion from the following obfervation, viz. 
that matter vomited by infants of a few days old is 
yellow, while it becomes white in a fortnight or three 
weeks. This he accounts for from the yellow colour of 
the cream thrown up by the milk of women during the 
firft four or five days after delivery. 
Mr. Clarke likewife controverts that common opinion 
of the human milk.being fo prone to acidity, that a great 
L 379 - 
number of the difeafes of children are to be accounted for 
from that principle. Whoever (fays he) takes the 
trouble of attentively comparing human milk with that 
of ruminant animals, will foon find it to be much lefs 
prone to run into the acefcent or acid procefs. I have 
very often expofed equal quantities of human and cow’s 
milk m degrees of temperature, varying from the common 
fummer heat, or 65°, to ioo°; and I have conftantly found 
that cow’s milk acquires a greater degree of acidity in 
thirty-fix hours than the human did in many days : cow’s 
milk becomes oftenfively putrid in four or five days • a 
change which healthy human milk, expofed in the fame 
manner, will not undergo in many weeks, nay, fometimes 
in many months. I once kept a few ounces of a nurfe’s 
milk, delivered about fix or feven days, for more than 
two years in a bottle moderately corked. It flood on the 
chimney-piece, and was frequently opened to be exa¬ 
mined. At the end of this period it fliowed evident 
marks of moderate acidity, whether examined by the 
tafle. I'm ell, or paper flained with vegetable blues or pur¬ 
ples ; the latter it changed to a florid red colour, whereas 
cow’s milk kept a few days changed the colour of the 
lame paper to a green, thereby clearly fhowing its putref- 
cent tendency.” 
Our author proceeds to ftate feveral reafons for his opi¬ 
nion, that the greater number of infantile difeafes are not 
owing to acidity. 1. Women’s milk in a healthy ftate 
contains little or no coagulable matter, or curd. 2. It 
fhows lei's tendency out of the body to become acefcent 
than many other kinds of milk. 3. The appearances 
which have been generally fuppofed to characterize its 
acidity do not afford fatisfadlory evidence offuch a mor¬ 
bid caufe. 4. Granting this to be the cafe, we have plentv 
of mild ablorbents capable of deilroying all the acid 
which can be fuppofed to be generated in the bowels of 
an infant; yet many Ghildren are obferved to die in con- 
l'equence of thefe difeafes fuppofed to arile from acidity. 
5. Though the milk of all ruminant animals is of a much- 
more acefcent nature than that of the human fpecies, yet 
the young of thefe animals never fuffer any thing like the 
difeafes attributed to acidity in infants. 6. Hiilory in¬ 
forms us, that whole nations ufe four curdled milk as a 
conftderable part of their food, without feeling any in-' 
convenience ; which, however, mull have been the cafe, 
if acidity in the Itomach were produiStive of Inch delete¬ 
rious effect as has been fuppofed. Irijh TranJ'. for 1788. 
In a memoir by Mellrs. Parmentier and Deyeux, mem¬ 
bers of the royal college of pharmacy, &c. in Paris, we 
have a great number of experiments on the milk of afles, 
cows, goats, Iheep, and mares, as well as women. The 
experiments on cows’ milk were made with a view to de¬ 
termine whether any change was made in the milk by the 
different kinds of food eaten by the animal. For this pur- 
pole fome were fed with the leaves of maize, or Turkey 
wheat; fome with cabbage ; others with fmall potatoes'; 
and others with common grafs. The milk of thole fed 
with the maize was extremely fweet; that from the pota¬ 
toes and common grafs much more ferous and inlipid ; 
and that from the cabbages the moll difagreeable of a!L. 
By diftillation, only eight ounces of a colourlefs fluid were 
obtained from as many pounds of each of thele milks; 
which from thole who fed upon grafs had an aromatic fla¬ 
vour, a difagreeable one from cabbage, and none at ait 
from the potatoes and Turkey wheat. This liquid be¬ 
came fetid in the fpace of a month, whatever l'ubllance the 
animal had oeen fed with, acquiring at the lame time a 
vilcidity, and becoming turbid ; that from cabbage gene¬ 
rally, but not always, becoming firft putrid. All of them 
feparated a filamentous matter, and became clear on being 
expofed to the heat of 25° of Reaumur’s thermometer. 
In the.refiduums of the diftillation no difference whatever 
could be perceived. As the only difference therefore ex¬ 
iting in cows’ milk lies in the volatile part, our authors 
conclude, that it is improper to boil milk either for com¬ 
mon or medicinal purpol'es. They obferved aifo that any 
ludden.. 
