80 ON THE RESERVE PROTEIN IN PLANTS. 



called proteosomes, with a high refractory power for light. T) 

 Upon treatment with iodine solution, they assume a yellow tinge 

 and lose their brightness entirely, showing either numerous little 

 vacuoles or one large one and being then hollow spheres. To 

 distinguish them from starch granules or fat drops is, there- 

 fore, a very easy matter. Sometimes it suffices to take a little 

 piece of fresh bark or a leaf and tear it into little particles 

 in a drop of coffein solution and observe the result at once 

 under the microscope with a high magnifying power. Thus, 

 not only the bright drops mentioned can be seen very soon, 

 but also in some early dying cells the change from the bright 

 drops to hollow spheres can be observed even without killing 

 with iodine. 



With regard to the behavior of the proteosomes, I observed 

 the following: the petals of Saxifraga sarmentosa which had 

 remained in cold saturated coffein solution and showed then 

 numerous proteosomes, were left for 15 hours partly in 1 % HC1, 

 partly in 1 % HN0 3 , and partly in dilute phosphotungstic acid. 

 The proteosomes were not dissolved but had become turbid. 

 Nitric acid had produced a yellowish coloration which became 

 stronger on heating. 



The petals of Punica granatum were, after treatment with 

 coffein, placed (a) partly in 1 p. mille NH 3 , (b) partly in 1 % 

 acetic acid and (c) partly in alcohol of 20%. After 4 hours it 

 was observed that the dilute NH 3 had not produced any vacuoles 

 in the proteosomes ; it seemed that they had become solid, and 

 neither absolute alcohol nor NH 3 of 10% nor acetic acid of 

 1 % changed them any farther. The portion exposed to the 

 dilute acetic acid (b) showed coagulated masses of irregular 

 form which were not changed any more by absolute alcohol. 

 A portion of proteosomes seemed to have been partly dis- 

 solved. Those proteosomes (c) which had remained 4 hours 

 in alcohol of 20 % were partly transformed to hollow spheres, 

 partly to irregular masses which experienced no farther change 

 by treatment with absolute alcohol. 



1) Dead cells never give proteosomes on treatment with coffein. If leaves of 

 Paeonia albiflora, for instance, are left for 24 hours in 1 °/ 0 acetic acid or for 1 hour 

 in vapors of ether, coffein will not produce any more proteosomes while the fresh 

 leaves give a very strong reaction. 



