1868. ] Chemistry. 567 — 
5. CHEMISTRY. 
M. Martin has made some experiments upon the preservation of 
meat by means of ether. He placed in six tin boxes uncooked beef, 
surrounded by little tufts of cotton wool soaked in sulphuric ether ; 
the boxes were then soldered tight, and exposed to the rays of the 
sun. Every three months a box was opened. Lach piece of meat 
weighed a kilogramme. At the end of three months there was no 
alteration either in weight or form. The meat thus preserved does 
not undergo the putrid fermentation; it is strongly impregnated 
with ether, and the odour remains after numerous washings with 
cold water. When cooked the meat possesses a peculiar savour, 
probably due, M. Martin says, to the formation of a new ether: 
the fibre is disintegrated. The process is not applicable to the 
preservation of food, but other animal matters might perhaps be 
advantageously treated by it. 
An ingenious method of testing fatty matters, founded upon the 
solubility of rosaniline in certain fatty acids, has been devised by 
M. Jacobsen ; it is applicable, among other things, to the examina- 
tion of cod-liver oil. A little piece of dry rosaniline placed in a 
sample of perfectly neutral oil, agitated and heated upon the water- 
bath, remains undissolved, but if placed in a rancid oil, a red tint is 
rapidly developed. Oleic acid and the other fatty acids dissolve 
rosaniline in large quantity, and become opaque from the depth of 
the tint, because oleate of rosaniline is soluble, in all proportions, in 
oils and other fatty substances. This property enables the presence 
of fatty acids in oils to be detected. or instance in commerce we 
have had, for some years, pretended white cod-liver oils, which are 
only fatty fluids from very young animals, or veritable cod-liver 
oil which has been agitated with potash, allowed to repose, and 
filtered. Since the therapeutic effects of cod-liver oil depend essen- 
tially upon the amount of free fatty acids which it contains, neither 
of these white oils can be valuable. Genuine cod-liver oil agitated 
with a little rosaniline is promptly coloured red in the cold, and if 
heated upon the sand-bath the colour is very deep, while the bad 
specimens already referred to remain perfectly uncoloured. 
When an oil which is only slightly rancid contains but a small 
amount of fatty acids, the coloration often does not become sen- 
sible at first. In this case it is better to prepare a solution of 
rosaniline in absolute alcohol, add a few drops of this to the oil 
to be examined, and heat on the water-bath until all the alcohol 
has been evaporated. If no fatty acid exist, the rosaniline soon 
separates and rises to the surface, or when the oil is too thick, rests 
in suspension as a brown powder. Samples of ordinary oil occur- 
ring in commerce have given the following results :—Olive oil and 
