33^ 



members of the terpene group, although the other physical constants are similar. 

 The synthetically prepared menthanes boiled at a still higher temperature. 



From the results recorded under the experimental portion, it is ])robable 

 tiiat the hydrocarbon, C,„H,,, was present in the latex also ; l^int it was nut isolated, 

 so that its plnsical characteristics were not determined. 



The occurrence of nitrogenous substances in tlir latex is also of some im- 

 portance in this connection, as indicating the presence of enzymes. Yoshida 

 Trans. Chem. Soc. 1883, 83, 472"! discovered an oxidising enzyme which is supposed 

 to play an important part in the production of the Iacc|uer varnish from the sap 

 of the lacquer tree. It was shown by Bertrand (Compt. rend. 1897, 124, 1032) 

 that the ash contained up to 2 per cent, of manganese, and that the activity of 

 the enzyme was influenced by the amoimt of manganese present, so much so that 

 its action was in some cases considerably increased by the addition of manganese 

 salts. This enzyme " laccase " is, however, an oxidising one. 



In the latex of Araucaria C nnninghamii , manganese is also present, apparently 

 in weak combination. The manganese compound is, however, easily altered, even 

 on drying in the air, the formation of a higher oxide of manganese being most 

 pronounced. The influence of manganese here, if entering into the reaction, may 

 be due to the facility with which it forms compounds varying in the amount 

 of oxygen present, and may thus act an important part in the organic arrangement 

 of the atoms in the compounds which are found eventually in the latex. The 

 action of reducing enzymes (reductases) is not so well understood as is that of the 

 oxidising enzymes, although considerable advance has recently been made in this 

 direction. 



The gum found in the latex was apparently identical with the gum of 

 gum arable; it differed in some respects from the gum freshly obtained from 

 A. Bid'ailli, as it did not form an insoluble jelly when it was agitated with etlur 

 for a very long time. 



The resin of the latex of Araucaria Cunninghamii consisted of two resin 

 acids, together with neutral resins, a bitter principle, &c. The investigation of 

 this resin was carried out in a similar manner to that of the resin of Agathis rohnsta, 

 see under that species). The acid of high melting point was dextro-rotatory, 

 crystalline, and was identical with the corresponding acid obtained from Agathis 

 rohnsta ; it was, therefore, Dundathic acid. The acid of low melting jioint could 

 not be obtained in a crystalline condition, but was separated from an aqueous 

 solution as a soda salt ; it was not, however, so rom])letely separated in this way 

 as was the corresponding acid in the resin ot Agathis robiisla. It gave 

 results indicating the formula C.,„H,„0,. It was l;evo-rotatory, thus differing 

 from the low melting acid of Agathis robusta, wliieh wa^ ilextKi-iotatorv. 



