The transformation was very much favoured by repeatedly inter- 
rupting the illumination and redissolving and recrystallising the mass. 
The addition of benzoic acid, a- or g-truxillie acid to the allo- 
cinnamic acid (?/, gram alloacid +1 gram of the other acids) was 
found to be injurious, whereas the admixture with cinnamic acid 
was very advantageous. From half a gram of alloeinnamie acid 
alone, 0.264. gram of g-truxillie acid was formed, whilst this quantity 
of alloacid when mixed with one gram of 7-cinnamic acid had yielded 
0.707 gram of 3-truxillie acid. 
This result is, therefore, quite in harmony with what was found 
previously. 
This increased yield of 3-truxillie acid on adding normal cinnamic 
acid to the alloacid was formerly explained by me by assuming that 
B-truxillie acid might be formed from one molecule of ad/oacid and 
one molecule of normal cinnamic acid. It is, however, obvious that 
we should observe the same thing when „-einnamic acid itself was 
transformed into g-truxillie acid and when the alloacid formed 
B-truxillie acid indirectly over the n-cinnamic acid. 
Up to the present, however, the transformation of n-cinnamic acid 
into g-truxillie acid has not been observed. Riper *), CrAMICIAN and 
Si.Ber ?) and also myself when following Ruser’s plan of illumination, 
could not demonstrate a formation of 3-truxillie acid from 2-cinnamic 
acid. 
In order, however, to be able to make a choice of these two expla- 
nations, the following experiment was made. 
On three dishes (diameter 18 cm.) of equal size and shape were 
distributed in the manner directed 1 gram of «lloacid, 1 gram of 
n-cinnamie acid and '/, gram of «lloacid + '/, gram of n-cinnamic 
acid, respectively. The illumination took place for two hours in sun- 
light; after each half hour, however, the acids were redissolved and 
recrystallised. The following quantities of «- and g-truxillie acid were 
found to have formed. 
a 8 
1 gr. of allocinnamic acid trace 0.073 
1) ers, cinnamie, acid 0.417)0, 495 
er. ,, allo- +1 gr. normal cinnamic acid 0.013 _ 0193 
) Ber. 35, 2908 (1902). 
) Ber. 35, 4128 (1902), 46, 1564 (1913). 
) The transformation of #-cinnamic acid into z-truxillie acid was first noticed 
by’ J. Berrram and KürsteN [Journ. f. prakt. Chemie 51, 324 (1896) and Ber. 
28 IV, 387 (1896)]. 
] 
2 
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