1922] CURRENT LITERATURE 419 
Gnetum resemble those of angiosperms in their internal structure as well as 
in their general appearance. 
The conclusion for the entire group of gymnosperms is that the leaves 
belong to a single xerophytic type, with Ginkgo and Gnetum as the only excep- 
tions. The literature list is very incomplete, because it was not thought 
necessary to repeat references which can be found in standard texts.—C. J. 
HAMBERLAIN. 
Respiration of thermophiles.—The respiratory activity of the thermophile 
fungi, Thermoascus aurantiacus, Anixia spadicea, and others, has been studied 
by Noack," who finds that the high respiratory activity is directly related to the 
rapid growth rate of these organisms, and that it is merely a consequence of 
the high temperature, not due to specific constitution or peculiar enzyme 
equipment. The economic coefficient for young cultures is 1.8, and about 3.6 
temperature coefficient of respiration in thermophiles, which is about 1.7 within 
the temperature limits for growth Gs —55°), with that of Penicillium, which is 
about 2 at 15°-25° C., NoAcK des that the thermophiles show a restricted 
respiration. Thus, Tisdmeicies produces 310 per cent of its dry weight of 
CO, in 24 hours. If the respiratory rate of Penicillium at 25° C. were quad- 
tupled by a rise to 45° C., however, it would produce 532 per cent of its dry 
weight of CO, in 24 hours. From this consideration of the vAN’T Horr rule, 
and the absence of abnormal behavior in respiration and growth, he concludes 
that the high respiration of thermophiles is merely a temperature consequence, 
and is really somewhat restricted for that temperature. 
With regard to this use of the vAN’r Horr rule, and the finding of a lower 
temperature coefficient of respiration for thermophile fungi at 45° C. than for 
Penicillium at 25° C., attention is called to a recent paper by Matisse," who 
criticizes the use y = van’r Horr rule, and urges the adoption by biologists 
of the ARRHENIUS temperature law instead. The formula for the van’t Horr 
rule is ARCS RY with that developed by ARRHENIUS, and the latter is now 
accepted universally by physical chemists. The curves developed from each 
shows that as the temperature goes higher, the value of Q,o decreases. The 
lower temperature coefficient for thermophiles is exactly what one would expect 
according to the ARRHENIUS temperature law, and the argument that thermo- 
philes show a herein, respiration for that temperature (45°) is probably not 
justified —C. A 
"Noack, Kurt, Die Betriebstoffwechsel der thermophilen Pilze. Jahrb. Wiss. 
Bot. 95:413-466. 1920, 
™ MATISSE, Gachaan La loi d’Arrhenius contre la régle du coefficient de tempér- 
ature. Archiv. Int. Physiol. 16: 461-466. 1921. 
