— 88 — 
caryophyllene, patchoulene, guajene, and the alcohols belonging thereto, 
and finally also on oil of carline thistle, but these in the main only 
confirm already-known facts concerning these compounds. 
Of the chemistry of Para caoutchouc little is known. Contrary 
to other w^ork of older date, Weber i) held the opinion that caout- 
chouc represented an aliphatic polyterpene with two double linkings 
each on one molecule C^qH^q, as he obtained from it tetrahalogen 
compounds of the formula (CiQH^gX4)n. Harries 2) supports this 
view. In the degradation of the caoutchouc molecule he obtained, 
by means of nitrous acid, under various conditions, nitrosites of a di- 
molecular terpene, which resembled the nitrosites of dimyrcene, a poly- 
merisation-product of the aliphatic terpene myrcene. The process of 
reaction appears to be accomplished thus, that first of all nitrosites of 
a tetraterpene are formed, and on further oxidation diterpene deriva- 
tives. In the pyrogenic polymerisation of cyclic terpenes, such as limo- 
nene, dipentene, and others, no bodies were obtained which under the 
same conditions yielded addition-products with NgOg. Dipentene which 
is stated to occur in large quantity in the distillation of caoutchouc, 
but which was only obtained in a yield of about 15 per cent, is, ac- 
cording to Harries, produced by secondary formation from isoprene 
or the hypothetic diisoprene, and not from caoutchouc direct. 
Alcohols. 
For the detection of bodies containing hydroxyl (alcohols, phenols, 
or oximes) Tschugaeff^) recommends that the substance to be 
examined be brought into reaction with organic magnesium compounds 
of the formula R • Mg • I , such as C H3 • Mg • I. In the presence of 
a hydroxyl - group methane is formed according to the equation 
CH3 Mgl -f R . OH = RO . Mgl -j- CH4. As these Mg-organic com- 
pounds of alcohols etc. are non-volatile, this method can also -serve 
for their separation from volatile indifferent bodies, such as hydro- 
carbons, as the latter can be distilled off in vacuo. 
In the "Archiv fiir experimentelle Pathologie und Pharmacologic" 
vol.48 (1902), 223, E. Erdmann reports more in detail on the pharma- 
cological action of furfur alcohoH). 
The experiments on animals and on men show that this constituent 
of essential oil of coffee possesses toxic properties which are not 
^) Berliner Berichte 33 {1900), 779; 35 (1902), 1947. 
-) Berliner Berichte 35 (1902), 3256; 4429. 
^) Chemiker Zeitung 26 (1902), 1043. 
^) Compare also Report October 1902, 31. 
