AUGUST, 1940 INDUSTRIAL A N D l3NGlKl<KIi lSG ( :HEMISTRY 1147

Tarr.~ IX. KEEPING TESTS ox <:RUDE LEAF t ' a ~ n r ~ ( A w MONiUU SULFATE PRECIPITITE)

bliik-Clotting Units/Mg. Solid Mattcr -. Months st F0t

Room Temp. activated Activated- 0 0 . 1 0.3

a 0 . 1 1 0 . 1 o.ao 4 0 . 0 5 o:ia 5 0 0.05

15 0 o 0 Each t ~ s t (made with 1.0 cc oi enzyme pre arstio") W ~ S activated by

addins I drop of2 dl NaCN and allowing to 8tam?&7 minutes.

however. The alkaloid may be extracted with benzene after the preparation is dry.

Both alcohol and ammonium sulfate are reagents that may be recovered in some measure after use-the former by dis- tillation, the latter by crystallization from the evaporated mother liquor. The addition of 2 volumes of alcohol to the mother liquor without prior evaporation precipitated nearly all the ammonium sulfate. This was filhred off and the alcohol then recovered by distillation.

The keeping quality of such preparations is naturally an important factor in evaluating them. The bettor prepara-

tiuiii ilescrii~ed i n Table VI11 were found to retain their activity quite well for 2 months but were not followed there- after. Another leaf preparation made like example b of Table VIII, but in larger amount, behaved as shown in Table IX. It is apparent that the keeping quality of crude leaf papain is not so good as that of commercially dried latex, although the latter is not very stable.

It appears, therefore, from the behavior of press juice from the leaves and stalks of the papaya tree that methods of ob- taining "leaf papain" are chemically possible. Further puri- fication of such preparations, resulting in both higher proteo- lytic activity and better keeping quality, is necessary before a satisfactory technical process can he suggested. Then engineering and agrononiic questions will require attention before such a process can be regarded as commercially valu- able.

Literature Cited ( I ) Bails and Hoover, J . Bioi. Chem., 121, 7 3 7 4 5 (1937). (2) Balls and Lineweaver, Ibid.. 130, 669 (1939). (3) Balls, Swenson, and Stuart, J . Assoc. Oficiel Am. Chem., 18.

14+6 (1935).

Conrsrea~ioa i G 5 f rom the Food Rosearch Divieioe, U. 8. Bureau of Agri- cultursl Chemistry and Engineering.

THE ALCHEMIST

By David Teniers, the Younger

Again w e are indebted to Mr C. G. Fisher of Pittsburgh for another painting by that prolific artist, the younger Tcniers (1610- 1690).

Mr. Fisher's painting, purchased by him in London in 1928, is a copy of an original, signed "D. Teniers", and located in the Prado Museum in Madrid. The latter is 32 by 25 centimeters in size. The

properties", background, and style are ' 1

typical of thc artist. This is No. 116 in the Berolzheimer

series of Alchemical and Historical Re- productions. 50 East 4ist Sriecr New York, N. Y.

D. D. B m o ~ z m ~ s a