324 
hour. Upon examination it was found that the new rays had not © 
induced any curvatures. A further exposure of one-half hour 
induced no curvatures. Afterwards the seedlings were exposed 
to one-sided diffuse sunlight, to determine whether any after 
effects would be manifest. It was found that the heliotropic 
curvatures took place promptly and proceeded normally. Frony 
these experiments the author concludes that the new rays differ 
from sun rays in that they do not cause growth curvatures. No 
observations were made as to whether the seedlings absorbed the 
Roentgen rays. 
Recently Hintenberger* has published some interesting re- 
sults in regard to the preparation of Roentgenograms of vegetable 
tissue. From some previous experiments made by K. Zahlbruck- 
ner and W. Konig it became apparent that certain tissues are very 
clearly outlined, especially the interior of the ovary. The author, 
with the assistance of Dr. A. Zahlbruckner, made a series of eX- 
periments testing the transmissibility of different flowers, buds and 
fruits to the Roentgen rays. From the Roentgenograms obtained 
it was found that not all ovaries gave the same clearness of out 
line. Seeds having a comparatively low percentage of water and 
a large number of air chambers and passages gave the best results, 
as for example beans and peas. Fleshy fruits transmit the new 
rays with difficulty. The interrupted water columns in the vessels 
of the stem ofa species of Nuphar were outlined. : 
Further Roentgenogramic experiments with dried herbarium 
specimens, of seedlings, woody tissues, etc., are in progress. The 
author ventures the suggestion that vegetable tissue may perhaps 
be made more readily transmissible to the new rays by impregna- 
tion with various solutions, such as solutions of lead salts, etc. It 
is also his opinion that the sénsitive plates can be made to respond 
more effectually to the influence of the Roentgen rays. ‘ 
KE 
*Hintenberger, Hugo von, “ Réntgenogramme ” von Planzentheile. Separatab- 
druck aus der Photographischen Correspondenz, . 1896. 
