278 Physiologie. — Algae. 



succulence results from the conversion of Polysaccharids into pen- 

 tosans or mucilages, and xerophytism from a conversion of the 

 Polysaccharids into the anhydrides or wall material, both transfor- 

 mations being induced by a depleted or lessened water supply in 

 the cells." W. B. McDougall. 



Rankm, W. H., The penetration of foreign substances 

 introduced into trees. (Phytopathology. VII. p. 5 — 13. f. 1. 

 Feb. 1917.) 



Experiments with lithium nitrate show a very complete pene- 

 tration to places where there is an active translocation of food 

 materials. Trelease. 



Paulsen, O., Plankton and otherbiologicalinvestigations 

 in the sea around the Faeroes in 1913. (Meddelelser fra 

 Kommissionen for Havundersöeelser. Ser. Plankton. I. N° 13. p. 

 1—27. 6 textfigs. Köbenhavn 1918.) 



The lirst part is a description of the Laminaria forests in a 

 fjord (Frangis vaag) in the Faeroes. These forests play an im- 

 portant economic röJe, producing organic matter and being hide- 

 places for fishes and other animals. An annexed chart shows that 

 the Laminaria forests are distributed every-where within the 20 m 

 curve but as a rule they do not extend fartber out. 



A list of bottom diatoms is given, after the determinations of 

 E. Oestrup. 



The second part is a detailed investigation of the plankton of 

 the same fjord. From May 28th to June 16th a water sample was 

 taken every day in the inner fjord and the plankton was later 

 centrifuged out and counted (Gran's method). Only light variations 

 in the composition of the (neritic) plankton were found, whereas 

 the quantity was greatly changing. This is compared with another 

 series of samples, taken on different days with plankton nets from 

 the innermost part of the fjord to the water outside it, thus giving, 

 as it were, longitudinal plankton sections of the fjord. Here, both 

 quantity and quality were different, the outer fjord having partl}' 

 another plankton than the inner. A comparison of the two series 

 brings the Suggestion, that fiuctuations in both quantity and quality 

 originale from alterations in the currents, ingoing surface-current 

 bringing outside species in and packing the true fjord-species clo- 

 sely together, whereas outgoing current would carry fjord-species 

 out to the mouth, thus dilute the inner plankton, and prevent out- 

 side species from moving in. 



The currents themselves have not been pointed out; hydrogra- 

 phers have been able to find only very slight currents in Fran- 

 gis vaag. 



The third part of the paper is an investigation as to stomach 

 contents of fish. 



The fourth part deals with the plankton of the Faeroe Bank, 

 lying ab. 50 miles S.W. of the Faeroes and surrounded by deep 

 water. Countings were made. The plankton above the Faeroe 

 Bank is partly neritic, and its quantity is often greater than that 

 of the surrounding deep water. The bank water being also colder 

 and fresher than the surrounding water all things point to an intro- 

 duction of water from lower depths by means of vertical currents, 

 in other words a mixture of water la} r ers occasioned by the bank. 



