1831.] 
Notices of European Science . 
231 
a funnel, the aperture of which is stopped, and left until a layer of cream has 
collected on the surface. After removing this, a little sulphuric acid is to be 
added, which will form a clot of sulphate of caseum ; this is to be well washed 
and then heated in water, with just enough carbonate of potash to dissolve it. 
The mucilaginous liquor formed is, whilst hot, to be mixed with its volume of alco- 
hol. It is necessary that no deposit form at the moment ; it should occur only in 
the course of twenty-four hours, and will include the butter, the sulphate of 
potash, and part of the caseum. All is to be placed on a cloth, and a clear trans- 
parent liquid will pass, which evaporated to dryness, leaves caseum pure, except 
in retaining a minute portion of potash. 
Caseum, or caseic acid, thus obtained, is a dry diaphanous substance, resem- 
bling gum arabic in appearance, and unalterable in the air. It reddens litmus pa- 
per, is soluble in hot or cold water, forming transparent viscid adhesive solutions, 
yielding by evaporation transparent pellicles, which again dissolve in water. The 
mineral acids, except the phosphoric, when added to the liquor, unite with the 
caseum, and produce white, opaque, coagulated insoluble masses. Very weak so- 
lutions are not thus coagulated, as may be seen by adding a little diluted sulphuric 
acid to such ; heat does not cause the effect, but the moment a little lime is added 
it happens at once. Milk, with twice its bulk of water, is not coagulated by sulphu- 
ric acid cold, but apply heat and the effect is produced, because a little phosphate 
of lime in the milk then becomes sulphate, and acts as above generally ; the com- 
binations of cheesy matter with acids are imputrescent. Well washed sulphate of 
caseum was left with water for a long time ; it gradually disappeared, but pro- 
duced no putrid odour. 
Vegetable acids precipitate caseum, unless in excess ; potash, soda, and ammo- 
nia produce very soluble compounds with it, which are perfectly transparent, un- 
alterable by air, and resemble gum. All earthy bases and metallic oxides form 
insoluble compounds. All salts, except those with base of potash, soda, or ammo- 
nia, combine with caseum to form insoluble compounds. Even a little selenitic 
water put into a solution of caseum, though it causes no change at first, yet, 
when heat is applied, produces insoluble pellicles, which are a compound of the 
caseum and earthy salt. The same or still more striking coagulation happens 
with sulphate of magnesia, and acetate of lime. 
Strong alcohol does not affect caseum, weak alcohol dissolves it, sugar renders 
a solution of caseum more liquid, gum arabic renders it quite insoluble, probably 
from the presence of earthy salts in it. Infusion of galls acts with it as with gela- 
tine. M. Braconnot suspects that vegetable albumen is nothing more than caseum 
with some earthy salts present. 
Improved Milk. — Besides caseum and butter, milk contains salts, &c. which arc 
not particularly desirable. M. Braconnot took 2£ litres (4. 4 pints) of milk, 
heated it to 113° F., gradually added dilute muriatic acid, and agitated the whole. 
1 he curd formed contained the caseum and butter, and being separated from the 
whey, was gradually mixed with 5 grammes (77 grains) of crystallized sub-carbo- 
nate of soda, reduced to powder and warmed. No water was added, but the whole 
Mf d’ 880 ^^ ^ had the weak acidity of recent milk, and formed about a 
alf-litre of cream (a fifth of the first bulk), capable of numerous applications in 
domestic economy. If made up to its first bulk with water and a little sugar, it 
orm s a rnilk more agreeable than the original, or it may be flavoured, &c. and 
a v j ( as cream. If it be heated with about its weight of sugar, it becomes remark- 
* ). **uid, and forms a perfectly homogeneous syrup of milk, which will keep for 
wat Pn f °f t* me ) and which, by the mere addition of a sufficient quantity of 
SD /tV 0rm8 a perfectly homogeneous white opaque liquid, which is in every re- 
ji ' 0 . 1 . e sugared milk of improved flavour. The syrup diluted with water forms a 
or th* S > ? g f°r invalids, carefully evaporated, but not beyond a certain limit, 
for • *t , tter would separate ; it gave, when cold, a soft confection, which left 
ex _ . reruonth in a loosely stopped bottle, underwent no change. This, when 
crush 1 m P ort * ons t° the air, was rendered quite dry, and could then be 
hie inf 1 HIU ^ ^ or an y of time without change, being always reconverti- 
0 useful states by the mere addition of water. 
