an investigation of the transpiration current in submerged plants 

 studying various species of Potamogeton and other aquatic plants. 

 The results showed that there was a decidedly rapid movement of 

 water in detached rootless stems of Potamogeton lucens and that 

 this current was largely dependent on the leaves. 



PEIRCE and MOLISCH. The temperature of respiring plants. 



Gard. Chron., 3 ser., 45 (1909), No. 1161, 200. (Reviewed in 

 E. S. fi. t Aug. 1909). 



A review is given of some recent investigations by Peirce and 

 Molisch on the temperature of respiring plants. 



Peirce has recently shown the value of Dewar flasks for use in 

 determining the rising temperature due to the respiration of seeds, 

 peas giving an increase of temperature from 17 C. to a maximum 

 of 56 in 8 days. 



In the experiments of Molisch cited, leaves of different trees 

 were used, precautions being taken to prevent any loss of heat by 

 radiation. It was found that the temperature within the mass of 

 leaves rose rapidly, in the course of 12 to 15 hours the tempera- 

 ture of apple leaves rising to 59 C., hornbeam 51.5 and linden 50.8. 

 The leaves of a number of other plants, particularly evergreens, 

 gave less striking results. 



In both experiments there is said to have been no question of 

 any fermentation, the action being simply that of the normal re- 

 spiration. In the experiments of Molisch, when the experiment 

 was stopped before the highest temperatures were reached, the 

 leaves upon examination were found to still be alive and fresh (i). 



(i) Compare with: 



H. MOLISCH. Ueber hochgradige Selbsterwarmung lebenderLaubbldtter. Bot. 

 Zeitung LXVI, 1908, I Abt. p. 211-233, m i r 2 Text fig.; reviewed in Just's 

 Botanischer Jahresb. XXXVI Jahrgang (1908). Erstes Abt. V Heft. Leipzig, 

 1910, p. 686. 



By using large quantities of living leaves (3 to 5 Kgr.) and protecting 

 them from the cooling influence of transpiration and of radiation, H. Molisch 

 observed remarkably high temperatures, the rise of temperature occurring within 

 the space of one day. The following are maxima temperatures observed in the 

 case of leaves of some plants: Pyrus communis, 59 C.; Carpinus Betulus, 51. 5 5 

 Robinia Pseud-acacia, 51; Tilia spec. 5o.8; Juglans regia, 49.75 Salix Ca- 

 prea, 47. i; Cytisus Laburnum, 45.6; Vitis vinifera, 43-3 C. (Ed.). 



