SCIENTIFIC SUMMARY. 
109 
becomes of a yellow colour wlieii exposed to the influence of light, whether 
in vacuo or not. M. Sestini now appears in the field as an investigator of 
the properties of this compound, and he has made some very interesting dis- 
coveries. When the actinic rays are cut off by a solution of nitrate of uranium 
this peculiar change does not occur. Crystals of santonine, reduced to 
powder and exposed to light, not only change colour, but evolve a resinous 
odour, and acquire a very bitter taste. Water added to this altered santonine 
acquires a yellow colour, an acid re-action, and a bitter taste. If now the 
mixture be distilled, an acid liquid will be produced, which reduces nitrate of 
silver and bichloride of mercury, and throws down acetate of lead as a white 
precipitate. When the distillate is evaporated to dryness, it gives a deep 
red-coloured resinous residue. When the coloured santonine is treated with 
water it almost entirely loses its odour, and when then treated with alcohol, 
it is in great part dissolved, giving a yellowish solution, Avhich, on evaporation, 
leaves a reddish yellow residue, most of which is soluble in ether. The 
etherial solution leaves an micrystallizable deposit of an amber colour, and a 
very bitter taste. From various experiments M. Sestini concludes that, by 
exposure to solar light, santonine is changed into formic acid, and an uncrys- 
tallizable substance much more soluble in alcohol and ether than santonine 
itself, and also a red resinous substance. He has termed the yellow uncrys- 
tallizable substance, provisionally, 'photo-scmtonic acid. — Vide Bulletin dc Ico 
Soc. Chimique, July, and Chemical Neivs, Sept. 3. 
Cholesterine an Alcohol. — This has recently been demonstrated by M. 
Lindenmeyer, who has succeeded in forming the ether, and who has also 
discovered this compound in considerable proportions in peas, beans, almonds, 
and other vegetable substances which contain much albumen. 
New Method of determining Water in Organic Substances. — This has been 
devised by M. Winckler, and is founded upon the change of colour which 
takes place in anhydrous chloride of cobalt, when it absorbs water. Dry 
chloride of cobalt may be easily dissolved in alcohol (density 0’792) forming a 
beautiful blue solution, but when hydrated bodies are placed in this latter 
they give up their water, and the result of this is that the solution acquires a 
reddish hue. The operation is begun by ascertaining the quantity of water 
which is required to give a fixed weight of cobalt salt a certain red colour. 
M. Winckler states that he has found the process both practicable and 
efficacious. 
A new Alhumenoid substance in Milk has been discovered by two French 
chemists, MM. Millon and Commaille. It has hitherto been believed that 
casein is the only proteine compound in milk, but these chemists have shown 
that after this has been removed there remains a substance which possesses 
many, though not all of the characters of albumen. They precipitate the casein 
with acetic acid, and the filtrate, when heated, produces a coagulum which 
contains 15 '6 per cent, of nitrogen. The new substance, which they propose 
to term Lacto-proteine, has the following characters : — It is not coagulated 
by heat, nor by nitric acid, nor by bichloride of mercury, nor even by the 
combined action of acetic acid and heat. It is but slightly affected by 
concentrated alcohol, but is readily precipitated by an acid solution of the 
nitrate of binoxide of mercury, the precipitate, however, re-dissolving in 
excess of the precipitant. 
