152 TEANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



last weight is the dry weight of the specimen and from it 

 the percentage of water which was previously present can 

 be calculated. 



In experiments made with Dicranum scoparium the 

 upper leafy portions of the stem were taken and kept air 

 dried for 3 months at 18°C. to 20°C. The leaves and 

 leaf cells are for the most part living, and on making cell 

 preparations with Bacteria show in most cases as soon as 

 examined but in others not till after the lapse of an hour 

 or so, an active evolution of oxygen, i.e., the absorption 

 of water is almost immediately followed by a resumption 

 of assimilation, even after so long a dormant period. If 

 assimilation is active it is safe to conclude that respiration 

 is active also. Direct evidence is also afforded by keeping 

 the moistened plants in a gas chamber filled with air 

 deprived of C0 2 , along with a hanging drop of a weak 

 alkaline solution of phenolpthalein or of an aqueous 

 solution of BaH 2 2 . If 2 or 3 plants are used the drop 

 of phenolpthalein commences to fade in 10 — 15 minutes, 

 which indicates that the return of respiration is practically 

 simultaneous with the absorption of water by the dried 

 plasma. A sample of such dried plants contained 8*18% 

 of water. After being dried in the dessicator at 35°C. for 

 several days, until the weight shows no further appreciable 

 diminution, the plants still contained 1*78% of water. 

 Another sample of fresh plants, after being air dried for a 

 few days, contained 15 '88%, and after being in the 

 dessicator at 35 °C. until the weight remained constant 

 contained 2*07%, of water. 



Plants of Cladonia rangiferina kept air dried for 3 

 months at 15°C. to 20°C. are almost unaffected the 

 gonidia being almost all living. If moistened and rapidly 

 examined, at first no perceptible or only a mere trace of 

 an evolution of oxygen is shown, but this after half-an- 



