604 BARON LIEBIG “ ON A NEW METHOD OF BREAD-MAKING.” 
swer the question, What influence the time of collecting the leaves may have on the 
amount of prussic acid present ? In order to answer this question, he collected, every 
month during a whole year, fresh leaves of the Prunus Laurocerasus, and each time pre¬ 
pared with them aqua laurocerasi, according to the directions of the 4 Netherlands 
Pharmacopoeia.’ The results of this series of experiments are as follow:— 
Months. 
Quantity of Cyanide of 
Silver from one ounce. 
Milligrammes. 
Grains. 
(±) 
November, 1864 
December, „ 
6 drs. of leaves of laurocerasus, cut 
fine , digested for 24 hours with 12 drs. 
250 
3! 
January, 1865 
of water, at 59° F., 5 drs. being dis- 
170 
2 f 
February, „ 
tilled from the same in a glass retort. 
170 
n 
March, „ 
120 
1£ 
April, „ 
220 
8 * 
May, „ 
170 
H 
June, „ 
200 
H 
» 
250 
H 
August, „ 
300 
5 
September, „ 
240 
4f 
October, „ 
280 
4* 
From these results it appears that in 1865, a year in which the summer was very 
warm, and in which vegetable growth was extremely early and abundant, the leaves 
plucked in July yielded the largest quantity of cyanide of silver in the laurel-water. In 
the following year, the October leaves seemed to yield the strongest water. Of course 
the nature of the soil and of the weather may always modify these results. As to the 
mode of preparation, experience showed that the strongest water is obtained by cutting 
the leaves small, and thereupon distilling directly. To distil from the leaves whole is a 
quicker method, which usually affords a water which is still stronger than the Nether¬ 
lands Pharmacopoeia requires.— Selections from the Dutch Archives of Medical and Phy¬ 
sical Science , by Dr. Moore. 
BARON LIEBIG “ON A NEW METHOD OF BREAD-MAKING.” 
Baron Liebig has just made some important researches on a new method of bread¬ 
making. He remarks on the stationary character of this art, which remains to the present 
day much in the state in which it was thousands of years ago. He dwells upon the sanitary 
importance of the mineral constituents of grain, and the necessity of a sufficiently abun¬ 
dant supply of them in bread. These are best found in certain kinds of black and brown 
bread, which are, therefore, more wholesome than the white bread that is nevertheless pre¬ 
ferred by most people (especially by the lower orders), on account of its better appearance 
and superior palatableness. The problem has hence arisen, how to provide a beautiful white 
bread which shall contain all the essential mineral constituents of black bread. These 
mineral constituents (phosphate of potash, lime, magnesia, and iron) are introduced into 
the bread by the use of the baking-powder invented by Professor Horsford, of Cambridge, 
in North America. This baking-powder consists of two powders—the one acid, the 
other alkaline. The acid powder is phosphoric acid in combination with lime and mag¬ 
nesia ; the alkaline powder is bicarbonate of soda. Two measures made of tinned iron, 
the larger one for the acid powder and the smaller one for the alkali, are employed. 
When bread is required to be made, every pound of flour is mixed with a measure of the 
acid powder and a measure of the alkali powder, and sufficient water added to make 
dough, which is presently made into loaves and baked. In one and a half to two hours 
bread may be made by this process. The chemical change which takes place will be 
