576 Physiologie. — Palaeontologie. 



6. The presence of toxic organic substances in Solution was extre- 

 mely deleterious to the oxidizing power of the plants. The oxidizing 

 power of the plants, especially ofnitrites, was able to alleviate the 

 toxicity of such Solutions. 7. The process of oxidation is usually 

 accelerated by the addition of sodium nitrate to an aqueous soil 

 extract. The addition of other fertilizer salts also influences oxidaton. 

 8. The processes of oxidation by roots is largely if not entirely due 

 to the activity of a Peroxydase produced by the roots. This oxidi- 

 zing enzyme is most active in neutral or slightly alkaline Solutions. 

 The activity of the enzyme may be inhibited by the presence of 

 acid and also by the conditions in Solutions where anaerobic pro- 

 cesses occur. Trelease. 



Shreve, F., Transpiration and water storage in Stelis ophio- 

 glossoides. (Plant World, XL p. 166—172. Au. 1908.) 



A study of the amount and rate of waterloss in Stelis ophioglos- 

 soides for the purpose of ascertaining how long such plants can 

 survive without opportunity to absorb fresh supplies of water and 

 what relation exists between the normal rate of transpiration and 

 that obtained during conditions of severe drought. It was found that 

 the plant when deprived of its leaves, which alone serve as storage 

 organs, was able to cut down its water loss so that its reserve will 

 suffice to meet the demands of transpiration something short of 

 fifty days. It was also shown that if the external supply of water is 

 cut off, the transpiration rate is at once lowered and the plant 

 enters upon a period of reduced capacity for vegetative activity. 



Trelease. 



Silberberg, B., Stimulation of storage tissues of higher 

 plants by zinc sulphate. (Bull. Torr. bot. Cl. XXXVI. p. 489 — 

 500. fig. 1—4. D. 1909.) 



The effect of Solutions of zinc sulphate of various strengths 

 upon the formation of periderm and callus were ascertained. Various 

 kinds of tissue were tried but potato gave the best results, which 

 were as follows: Twelfth- and fourteenth-normal Solutions stimulated 

 the formation of meristematic tissue; a tenth-normal Solution neither 

 stimulated nor inhibited the formation of meristem. The potato tissue 

 recovered from the effects of eighth-normal Solution in eight or ten 

 days, from half-normal Solution in about seven days and from the 

 normal Solution in from thirteen to fifteen days. Observations upon 

 the effect of zinc sulphate upon the respiration of the storage tissue 

 of potato tissue, indicated that fourteenth-normal Solutions, or any 

 Solution stronger than that, inhibited respiration. A sixteenth-normal 

 Solution stimulated respiration. Trelease. 



Bertrand, P., Note sur les graines trouvees dans la breche 

 de'la fosse n°. 6 des Mines d'Ostricourt. (Ann. Soc. geol. 

 du Nord. XXXVII. p. 48-90. 1909.) 



La fosse n°. 6 des mines d'Ostricourt a traverse un banc de 

 breche forme de morceaux anguleux de schiste avec ciment greseux 

 grossier et renfermant de nombreuses graines de Pteridospermees, 

 appartenant les unes au genre Trigonocarpus, les autres au genre 

 Hexapterospermum. P. Bertrand a reconnu, pour le premier de ces 

 deux genres, quatre ou cinq especes differentes, dont trois du type 



