LACQUER WORK. 349 



Korschelt has pointed out further that the albumen present in 

 raw lac acts in drying as a ferment upon the lac-acid, and that the 

 hardening of the lacquer-paint is due to a process of oxydising, by 

 which the lac-acid taking up oxygen is converted into oxylac-acid, 

 according to the formula C^ H^g Oo + O = C^^ H^g O;^. When Kor- 

 schelt investigated still further this oxy-urushic acid which he ob- 

 tained in the form of a brown powder, he found that it is entirely 

 insoluble in all the solvents of lac-acid, and that both potash and 

 soda lye, ammonia in all degrees of concentration and of every 

 temperature, and most acids, strong saltpetre excepted, have no 

 effect upon it. It is therefore evident that the remarkable resist- 

 ance of dry Japanese lacquer-work to these influences is due to 

 the presence of this oxylac-acid. 



Korschelt's investigations and opinions do not favour the ac- 

 cepted theory that in the drying of lacquer-paint water is used for 

 making hydrates. But this leaves me without an explanation 

 of the thickening of the raw-lac to which 1 have alluded before, 

 especially of the Se-shime-urushi, when water is added, — a process 

 any one may observe, and in which a separation of the hydrogen 

 is not perceptible. 



In conclusion, I will mention the lacquer-poisoning or Urushi- 

 kabure as the Japanese call it, to which I have already referred 

 briefly on p. 343. It is a peculiar, not very painful, and not at all 

 fatal, but always very disagreeable disease, always attacking one 

 new to the work, whether he be lac-tapster, dealer, or lacquerer. It 

 appears in a mild reddening and swelling of the back of the hands, 

 the face, eyelids, ears, the region of the navel and lower parts of 

 the body, especially the scrotum. In all these parts great heat is 

 felt and violent itching and burning, causing many sleepless nights. 

 In two or three days the crisis is reached, and the swelling im- 

 mediately subsides. In severe cases, small festering boils form 

 also. This lacquer disease, admirably described by Father d'ln- 

 carville on page 119 of his work, to which I have now frequently 

 alluded, is not only caused by direct handling of the lac, but by 

 its evaporation chiefly, especially that of the sharp Se-shime, to 

 which I owed my own illness. 



The poison, however, is a volatile substance, and has nothing to 

 do with the lac-acid and its higher oxydation, as Korschelt believed. 

 If the poisonous property disappears in the drying of the paint, 

 this amounts to nothing save that the volatile poison fully escapes 

 in this manner. A considerable part of it is driven off in the 

 preparation of the several kinds of lacquer, and by stirring in open 

 vessels. For this reason, the lacquers mixed with colours are 

 regarded far less dangerous than raw lac and its direct derivatives. 

 When such lac has been for a long time shut up in a closed box 

 or tub, the experienced workman turns away his face when the 

 vessel is opened that he may not inhale the accumulated vapour. 

 This is noted by d'Incarville also m the following : " II faut prendre 



