468 
FACTS AND OBSERVATIONS. 
having the skin and periosteum of a dark bluish-black colour. 
Their flesh, however, is perfectly white, and surpasses that 
of other poultry in flavour. Mated with other varieties, he 
has found the mongrel offspring to have a dark skin and 
periosteum, but the plumage is of the ordinary colour and 
character. 
Detection of Cantharidine. —Mr. Tichborne, in an 
article in the Chemical News, states that chloroform is the 
best solvent of cantharidine we have. In mixtures suspected 
to contain this principle of the blistering fly, for its detec¬ 
tion he proposes to add to every half pint of the fluid one 
ounce of chloroform. The whole is to be repeatedly shaken 
during the day, and left to subside until the next morning. 
The chloroform is then carefully separated with a funnel, 
and passed through bibulous paper. It is then allowed to 
evaporate spontaneously to dryness on a watch-glass. A 
small pellet of lint, he says, which had been previously teased 
out, about half the size of a pea, was moistened with a drop 
of olive oil, and with this little pellet the whole of the film of 
extractive matter was mopped off the w’atch-glass. The 
lint was then placed upon the arm, and covered witH a piece 
of goldbeater^s skin. When taken off, in three or four 
hours, considerable rubefaction had taken place, and after 
wiping it off with chloroform a large vesicle was formed. As 
small a quantity as one grain of flies was detected in solution 
by this means, and to look for less than this in a medico¬ 
legal investigation, he adds, would be useless, as this is much 
under a medicinal dose. 
Progress of Chemistry. —The active progress of che¬ 
mistry—perhaps the most active of modern sciences—leads 
continually to new results or to modifications of existing 
conclusions. Ozone has of late years been a very prominent 
subject of research and discussion; but further research 
shows that what in numerous instances was described as 
ozone is in reality nitrous acid or nitrate of ammonia; a 
fact now recognised by Schoenbein himself, the discoverer of 
ozone. One consequence of this fresh discovery should be 
to render observers cautious in the use of what is called 
‘^ozonometric paper;” that is, paper saturated with starch 
and iodide of potassium, for the purpose of determining the 
presence and quantity of ozone in the atmosphere. For if it 
be true that the paper when moistened for experiment does 
not indicate the presence of ozone, but the energy only with 
which nitrite of ammonia is produced during the evaporation 
