FACTS AND OBSERVATIONS. 
Ill 
rendering water beautifully transparent, and apparently free 
from all organic matter, is its strong recommendation. We 
ourselves have had a considerable experience of the Spencer 
filter, and we consider it an admirable one.— Ibid. 
Detection of Xanthine in Urinary Calculi.-— 
M. Lebon showed, at a late meeting of the Academy 
of Sciences of Paris, a calculus which M. Cruveilhier, 
jun., had asked him to analyse. The outer layer was 
composed of phosphate of lime mixed with ammoniaco- 
magnesian phosphates only one thirtieth of an inch thick. 
The next layer consisted of oxalate of lime, and was as thin 
as the first, but the bulk of the stone w r as made up of 
xanthine, and a small proportion of urate of lime. This 
nucleus, dissolved in hydrochloric acid, yielded beautiful 
crystals of hydrochlorate of xanthine in hexagonal lamellae. 
The usual mode of detecting xanthine is excellent when 
the latter is pure ; but when it is mixed with lithic acid or 
lithates, as is often the case, the common method is not satis¬ 
factory. M. Lebon has found the following procedure useful 
for separating lithicacid from the xanthine,being founded upon 
the solubility of xanthine in hydrochloric acid, and the in¬ 
solubility of lithic acid, in the same liquid. Let, therefore, a 
fragment of the stone, reduced to powder, be boiled in 
hydrochloric acid, and the fluid be filtered. The insoluble 
portion of the latter is lithic acid, and the substance held 
in solution is xanthine. The nature of both substances may 
then be made out very easily by watching their usual re¬ 
actions.— Lancet . 
A Source of Albumen. —Albumen is now produced 
on a large scale at Pesth, Hungary, and in North 
Germany, from the blood of animals. The serum sepa¬ 
rating when blood coagulates consists chiefly of albu¬ 
men. The best quality of albumen thus obtained is 
transparent and soluble in water, and is used for mordanting 
yarns and cloth. At Pesth blood is dried in flat iron pans 
by exposure to air at a temperature at from 100 to 112° F. 
From S000 pounds of blood about 110 lbs. of albumen is ob¬ 
tained, at a cost of 29 dols.; 16,200 eggs would yield the 
same amount of albumen at a cost of 96 dols. Although 
the cost of egg albumen is three times as great as that of 
blood albumen, the former is preferred for dyeing purposes, 
on account of its purity. Blood albumen of a second quality, 
darker in colour, but nearly all soluble in water, is used 
largely in the process of refining sugar, 
