52 
muscle fluids both in rest and active work, resulting finally in the pro- 
duction of animal heat and work. In other words, muscular activity 
and the production of animal heat were accomplished, like all Ver- 
wesungsprocessen, through the action of Verwesungsfermente (oxidiz- 
ing ferments) on the free oxygen of the air. (Traube ( 427 ’ 430 ).) 
In plants, under the influence of oxidizing ferments as go-betweens, 
oxygen accomplishes the conversion of soluble carbohydrates into 
cellulose, and in animals it converts soluble proteids into ferments. 
He goes on to say further that the lessons to be learned concerning 
oxygen are only limited by those to be learned of organic life itself. 
• 
OXIDASES (Laccase, Bertrand). 
A new impulse to the study of the oxidases was given by the beauti- 
ful researches of Yoshida, and later by those of Bertrand, on the 
changes occurring in the sap of the lac tree, Rhus vermicifera, and 
allied species. It had long been known to the Japanese that the 
milk-like sap of the lac tree dries and hardens on exposure to the air 
and turns brown and finally black, thereby yielding a lustrous, 
translucent varnish, which is highly prized on account of its luster 
and stability. In 1883 Yoshida ( 467 ) for the first time undertook an 
accurate investigation of these interesting changes. He found that 
the lac tree yields a strongly corrosive sap, which he called “urushi;” i 
this he found to consist essentially of four substances, Adz., water, 
urusliic acid, C 14 H 18 0 2 , gum, and a peculiar diastatic matter which 
possesses the power of transforming the urushic acid into oxy- 
urusliic acid, C 14 H 18 0 3 , through the action of the oxygen of the air, in 
the presence of moisture. He found that this nitrogenous compound 
loses this property when heated to 63° C. He was therefore led to 
conclude that in this substance we have an enzyme which lias the 
poAA^er of carrying oxygen to the urushic acid, thereby transforming 
it into oxy-urushic acid which is the basis of lac varnish. He also 
showed that urushic acid can be transformed into oxy-urushic acid 
by chromic acid. 
Eleven years later a more exhaustive investigation of the changes 
occurring in the sap of the lac tree was undertaken by the French 
chemist Bertrand ( 48 ' 49 ), with the result that Yoshida ’s previous 
results A\ r ere confirmed. According to Bertrand, the changes ob- 
served Avhen the fresh juice of the lac tree is alloAA’ed to stand in the 
air are brought about by the oxygen of the air under the influence 
of an oxidizing ferment (< diastase oxydante) to which he gave the name 
of laccase. After boiling laccase loses the poAver of bringing about j 
these changes. Hence he regards laccase as the provocative agent of 
the oxidation, and found it not only in the fresh juice of the lac tree 
but also in gum arabic and gum Senegal. According to Bertrand, the 
oxidizable substance present in the juice of the lac tree and which* 
