426 W. P. Wilson— Respiration of Plants. 
absorption tubes filled with barium hydrate, and so connected 
together by glass stopcocks that the current of air or gas, when 
passing through one tube, could be instantly turned aaa 
the other without interruption. Thus while the current 
In conducting an experi fen me fae were made first 
in air for several half sears then the air was de aia by 
paaatiahs took place. The last series in air was used to com- 
pare with the first, and it readily showed whether the seedlings 
had undergone any lasting change for want of oxygen. e 
temperature of the plants for any given experiment was not 
allowed to vary; also the yee bat air or gas was held con- 
stant for all the successive half 
A great advantage in the piabods here aigre lay in sub- 
jecting the same seedlings, first to air, and then to hydrogen ; 
thus the products of the respiration of the same ‘plants under 
these "es different conditions could be compared.* 
ge number of seedlings were employed (from one to” 
sauces Dandies according to size), thus ensuring the produc- 
tion of a comparatively large amount of carbonic acid in a 
short: space of time, with which much more accurate measure- 
ments could be made than with small paper es. The amount. 
of carbonic acid was determined by the volumetric method. 
ecording to the investigations of Wuriheae with seedlings 
of Vicia Faba, Phaseolus multiflorus and some others, the car- 
bonic acid excreted in short spaces of time, one to three hours, 
was found to be the same whether oxygen was present or not. + 
In the case of seedlings of Vicia Faba, with which Wortmann 
ostly experimented, I have found this to be substantially 
true; tor all other germinating plants, flowers, or parts of plants 
there was an immediate decrease in the cart nie acid produced 
when oxygen was excluded. The first half hour's respiration 
in hydrogen often yielded but one third or even one-fourth the 
pueais acid produced by the preceding half hour’s respiration 
in air, ter three or four consecutive half hours of Baie a 
cular respiration, sometimes from the very first, steady 
ecrease in the carbonic acid was cine ae every follamicy 
half hour. This was also found to be true for Vicia Fada. 
The following are the results obtained ‘oti. 
mann used two sets of sg aap 5 as nearly alike as selection would permit, 
in vacuum compared with o 
“ire Als ich jedoch die in mene. kurse a Zs raumen—nach der ersten, zweiten und 
dritten Stunde—-a hiedenen K Koblensi remengen mit einander verglich, so 
fand ich jeneneey ‘dass das i in ‘dieser Zeit durch intramoleculare Sara ausge- 
schiedene ey ure g 
Wortmann, | 
Lod 
