564 
_ ‘The Destruction of Chlorophyll by Oxi- 
dizing Enzymes,’ by A. F. Woods, Wash- 
ington, D. C. 
This paper details the results of experi- 
ments going to show that the Mosaic disease 
of tobacco is due to oxidizing enzymes 
rather than to a ‘living fluid contagium’ as 
suggested by Beijerinck. It also shows that 
these enzymes are unusually abundant in 
many other cases of variegation, and in the 
disease known as peach yellows and peach 
rosette ; and in these cases also ascribes the 
destruction of the chlorophyll to the ab- 
normal abundance of these ferments. 
‘The Effect of Hydrocyanic Acid Gas 
upon the Germination of Seeds,’ by C. O. 
Townsend, College Park, Md. 
In the experiments that form the basis of 
this paper, seeds in both the dry and damp 
state have been tested with different 
strength of gas and for different periods of 
time. In the case of dry grains and seeds 
it was found that they might remain for 
several weeks in an atmosphere of hydro- 
cyanic acid gas, many times as strong as is 
required for the almost instantaneous de- 
struction of insect life, without appreciably 
injuring their germinating power. Indeed 
the gas under these conditions slightly ac- 
celerates germination, and the subsequent 
rate of growth of the seedlings is slightly 
above the normal. 
Seeds that have been soaked in water be- 
come very sensitive to the presence of 
hydrocyanic acid gas. If the seeds have 
been soaked for twenty-four hours they can- 
not germinate if more than 0.080 of a grain 
of potassium-cyanide per cubic foot is used 
in generating the gas. Even 0.003 of a 
grain of potassium-cyanide per cubic foot 
has a very marked effect on the time 
of germination of seeds that have been 
soaked in water for twenty-four hours. If 
the grains and seeds have been soaked but 
six hours, they are more resistant than when 
soaked for a longer period; but even under 
SCIENCE. 
[N. 8S. Von. X. No. 251. 
these circumstances germination is dis- 
tinctly retarded by the pressure of hydro- 
cynic acid gas. 
‘Some Physiological Effects of Hydro- 
cyanic Acid Gas Upon Plants,’ by W. G. 
Johnson, College Park, Md. 
A brief report of the first precise experi- 
ments with hydrocyanic acid gas upon 
young fruit trees, both dormant and in full 
foliage. 
‘Etiolative Reactions of Sarracenia and 
Oxalis,’ by Wm. B. Stewart, Minneapolis, 
Minn. 
An anatomical examination of etiolated 
leaves of Sarracenia and Oxalis, shows the 
increase of length of supporting tissues by 
increase in size and multiplication of cells, 
and the new development of portions which 
functionate in light only. 
Etiolative reactions are almost purely 
adaptive in their nature. 
‘The Mycorhiza of Tipularia,’ by Julia 
B. Clifford, Minneapolis, Minn. 
The roots tipularia show some marked 
specializations of structure for adjustment, 
for the presence of an endotropic fungus 
with which a symbiosis is formed. The 
fungus is differentiated into a vegetative 
mycelium, with external] absorbent branches 
and internal branches serving as organs of 
interchange. 
‘Cultures of Uredinee in 1899,’ J. C. 
Arthur, Lafayette, Ind. 
Successful cultures of eleven species of 
Uredinez were made upon their host plants, 
showing the connection of ecidial and tel- 
eutosporic stages. The following is a list 
of the associated forms, the host plants, and 
nature of the cultures : 
1. Puccinia Convolvulus Cast. on Convolvulus sepium, 
and Zcidium Calystegiae Desm. on same host, with 
sowings of teleutospores. 
2. Puccinia Phragmitis (Schum.) Koern. on Phrag- 
mites communis Trin. and Acidiwm rubellum Pers. on 
Rumezx crispus L. and R. obtusifolius L. with sowings 
of teleutospores. 
8. Puccinia Americana Lagh. on Andropogon sco- 
