sTrr)ii:=^ in thk effixt (if kOntoen rays, etc. 259 



material used for iiTiidirttiou wfis (1) air-dricfl seeds (" trot-kene, ruhende 

 Samen "), (2), one day, two days and a few da^s' water-steeped seeds, (3) 

 those with nidifies, and (4) seedlings wliich pro\ioiisly li;id lieen germinated 

 ill tlio |X)t and were in the same state of growtl), and tl'.eir development was 

 oljserved. T1m> doses p:iven wore in the first oxpcrimeut of ten kinds, {. e., 5 H, 

 3.5 H, 2.5 H, 1.5 H, - H, - II, - H, - TI, - II, and — H. In the other 



2 10 20 40 01) Itlf) 



case, strong in-adiation was employed. 220-3,000 gi'ains of seeds were used 

 in every ex\x;riment, sown into a }X)t containing wet poplar saw-dust after 

 the irradiation and planted in o|5en ground after their first development. He 

 said that, " vuu den Versuclispflanzen wies eine sichtliche Beeinflussung des 

 Waclishims durch die Röntgenstrahlen eigentlich nur Vicia faJxi auf. Betreffe 

 der Keimung zeigten allerdings die übrigen Versuclispflanzen, außer den 

 Geti'eideaiien, bei welchen ülierhaupt keine Wirkung zu erkennen war, analoge 

 Verhältnisse wie Vicia faha, wenn auch in schwächerem Maße ". The results 

 of ex|X!riments were, (1) in the case of air-dried seed3 : the strongly in-adiated 

 germinated generally sooner than the weakly or uniiTadiated. At first there 

 wa^ a difference in gi-o^\tIi, l)ut they ^\■ere balanced in the flowering time, 

 (2) in the case of stee^Jed seeds; the one or two d;i3's steejjed gave the same 

 results as those under (1), in three flays steeped seeds, the growth of 3.5 H- 

 and 5 H-j^lants was impeded a little at first — there was a difierence proportional 

 t-j the doses given — liut aftei'W'ards it was balanced, (3) in the case of the 

 seeds with radicles, the gi'owth of 1.5 H was at firet inferior. But tl^.e growth 

 of - - H - — H seedlings was accelerated. A pai-t of these materials showed 

 marked differences at firet, but afterwards they wei"e j^eriectly balanced and 

 in the flowering time these i^lants showed a similar state of development to the 

 5 H-plants which were somewhat slender. Then he said, suppjiiing E. 

 ScHWAEz's statement, that " an den Ijereits im vorgerückton Keimungszustand 

 bestraldten Pflanzen WiU- von einer Förderung des Wachstums, auch nach 

 Applizierung der schwächeren Dosen, nichts zu liemerken. Bei den Dosen 

 von 3X ( = 1.5H) au aufwärts fiel diigegen besondere stark der schädigende 

 Einfluß auf: die Pflänzcheu blieben bald entsprechend der Intensität der 

 erhaltenen D(jsis in ihrer Entwicklung zra-ück ". When four weeks had passed 

 after tlie in-adiation, the 5 H-plaaits did not make any further growth. The 

 1.5 H-, 2.5 H- and 3.5 H-plants ceased to grow proportional to the doses given. 



