26 



ACTIVE ALBUMEN 



proteosomes, but if they had been treated with a neutral solution 

 of formic aldehyde (5-10 per cent), they would have lost their easy 

 solubility in caustic lyes, — exactly like the behaviour of ordinary 

 proteids, I observed some time ago. 1 ' — The Millons reaction is 

 obtained if the objects are left for 8-10 hours in a solution of 

 mercuric nitrate containing some potassium nitrite, and then 

 heated for a short time to the boiling point. — The " biuret- 

 reaction " is obtained on treating the proteosomes first with 

 diluted ammonia (0,1%), then for 12 hours with a dilute solution 

 of acetate of copper, and finally with dilute caustic potash. 2) — 

 While the fresh proteosomes soon disappear by treatment with 

 dilute carbonate of soda, such proteosomes, as were changed by 

 the death of the cells, offer considerable resistance to it. 



Of special interest is the behaviour to diluted ammonia, 

 whereby the proteosomes are solidified, another and marked dif- 

 ference from ordinary proteids being thus demonstrated. 3 ' These 

 solidified proteosomes are chemically not identical with the co- 

 agulated proteosomes mentioned before; the ammonia brought on 

 a different change, being taken up and having entered into an 

 intimate combination, which however has no salt-like constitution, 

 as the chemical behaviour clearly indicates. A dilute hydro- 

 chloric acid (0,5 per cent) will at 40°C gradually attack the 

 coagulated proteosomes, but not those solidified by ammonia. 

 Even a 10 per cent hydrochloric acid dissolves at 8o° the latter 

 ones with difficulty, compared with the former. This chemical 

 fixation of ammonia recalls the formation of pyrrols from 1.4 

 diketons or the formation of aldehyde-ammonia-groups, with 

 subsequent changes to a more intimate fixation of the nitrogen. 

 If aldehyde-groups be present in our labil proteosomes, the 

 behaviour towards ammonia can be understood, and as aldehydes 

 retain their silver-reducing properties even after combining with 

 ammonia, this question could be settled by experiment. But 

 care had to be taken to exclude every trace of other reducing 

 compounds as glucose or tannin, frequently occurring in plant- 

 cells. — 



1) Compare O. Locw, Jahresbericht f. Thierchemie 1892 p. 29 and 1888 p. 273. 



2) For further details see Botan. Centralbl. 1S89 Nr. 39 and 45. 



3) This behaviour to ammonia may serve in some cases to distinguish small and 

 indistinct proteosomes from tannates of coffei'n or antipyrin, which will be readily 

 dissolved by ammonia. 



