SCIENTIFIC’ SUMMARY. 
ill 
of cold diluted sulpliuric acid (3 parts of acid to 1 of water). When the 
solution is complete, 225 grammes of aldehyde are added, and the mixture is 
stirred. The whole is now heated in a water-hath. From time to time a 
drop of the mixture is taken up with a stirring-rod, dropped into acidulated 
water, and as soon as a deep green solution is obtained, the reaction is stopped. 
The mixture is now poured into thirty litres of boiling water, and to this 
solution is gTadually added 450 grammes of hyposulphite of soda, dissolved 
in the smallest possible quantity of water. The whole is now boiled for some 
minutes. All the green remains in solution — it is a beautiful hue, and is es- 
pecially so in artificial light, which serves to distinguish it from other shades 
of green,- prepared from different materials. When in this condition the 
^‘aniline green” may be directly employed in the dyeing of silk and similar 
fabrics. — ^Vide Artimn, August, 1864. 
Is Professor Graham the Discoverer of Dialysis ? — The following very im- 
portant statement is contained in the Paris correspondence of the Chemical 
News (No. 248). It bears upon the claim to priority of discovery of dialysis, 
and we doubt not it will soon receive contradiction : — On April 1, 1854, 
M. Dubrunfant (whose writings are familiar to most readers of French scien- 
tific literature) took out a patent for certain improvements in sugar refining, 
in the specification of which he declares, first, that when water and molasses 
are placed in a vessel separated only by an animal membrane, a weak current 
is set up between the two liquids ; and, secondly, that the water carries with 
it the salts contained in the molasses, that by their presence they prevent the 
sugar from crystallizing.. Graham’s celebrated Bakerian lectures on the 
osmotic force, in which he first explained the dialytic action of membranes, 
were not delivered until June 15 of the same year. The patent was subse- 
quently rendered useless by the discovery of the method of refining sugar by 
Baryta. M. Dubrunfant has, however, lately (June, 1863) patented a refining 
apparatus on the dialytic principle, in which the septa are made of parch- 
mentized paper. An experimental apparatus has been fitted up at the refinery 
of Courrieres, near Valenciennes. In this apparatus, not only are the salts 
separated by dialysis from the sugars, but the same means are adopted for 
separating the nitrate of potash which they contain from the other salts. 
The above statement would seem to imply that Professor Graham was not the 
first to announce the discovery ; but we have little doubt that there exists 
abundance of evidence to show that his discovery had been absolutely though 
not formally announced long before the 15th of June. 
Soluble and Insoluble Digitaline. — Two forms of this alkaloid are prepared 
for sale : one comes from Germany and is soluble in water and alcohol, the 
other is manufactured in France, and is but sparingly soluble in water. The 
German variety is said to be made by Merck of Darmstadt. It is of a 
yellowish-white colour, neutral to test paper, and completely and readily 
soluble in both alcohol and water. It is, on the contrary, but slightly 
soluble in ether, sulphide of carbon, and benzole. It is entirely precipitated 
from its aqueous solution by tannin. When dropped in a state of powder 
into hydrochloric acid, it immediately dissolves, forming a yellow solution, 
which gradually turns brown, and finally becomes green. The latter colour^ 
however, is not so bright as that produced by the unsoluble digitaline, 
although it remains transparent for a longer time. As the green colour is 
