68 Dr. H. T. Brown and Mr. F. Escombe. [Jan. 9, 
laboratory with feeble winter sunlight, when the amount of carbon dioxide 
evolved fell to 0°28 c.c. per square decimetre per hour. 
(b) Huperiments on Respiration. 
The abnormal respiratory effect observed in greenhouse plants during 
the winter months is shown in the following Table XV, and in Table XVI 
we have shown by way of contrast the normal respiration observed in certain 
leaves during the swmmer, the plants in this instance having been grown under 
ordinary out-door conditions. 
Table X V.—Winter Respiration of the Leaves of Greenhouse-plants. 





CO, respired 
Temperature, | per square decimetre 
Date. Name of plant. P C P ances ged 
centimetres. 
| December 14......... Senecio grandifolius 25°°2 5°12 
| a DO sesinee Dioscorea cayennensts 22-4 13°45 
An DO eee a5 * 19°-0 8°78 
he Denn a in he 19°-9 533 
_ eater | Plumeria lutea ...... 19°°7 2°49: 
| , hese te Begonia haageana ... 16°°5 3°38 
| ‘5 LS eee Sapium bolinense...... icky, Oh 8°98 



Table XVI.—Summer Respiration of Leaves grown under Out-door 



Conditions. 
CO, respired per 
Tempera- | square decimetre per 
Date. Name of plant. ture, C. hour in cubic 
centimetres. 
Ansusb922 7. 20s. 2 Helianthus annuus ... Fs | 0:429 
September 7 ...... 3 ery a3 26°°8 0:714 
TNE QO wrens. Petasites albus......... 18°:0 0°321 
Silva te Oe in Ga eee 95°°6 0+584 
puames oo WEL we) &, Polygonum Weyrichii 1S Or721 
lays See it is ” 25°-2 0-788 
Diy el eae caste 6 i s 36°°4 1:179 
It will be noticed that, except in the last instance, where the temperature 
was very high in the respiration case, the respiration of these leaves growing 
under normal out-door conditions does not average more than 6/10 c.c. of 
