ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 421 



fructification or on the colour of the cell-contents cannot be used for tlie 

 delimitation of the species ; the only ones which will stand at present 

 are those founded on the external form of the cells and on their arrange- 

 ment with respect to one another. Several species of TrentepoJiUa enter 

 into the composition of lichens, especially of those belonging to the 

 genus Coenogonium. The following new species are described : — T. 

 monilia and T. torulosa from Chile, growing on the bark of trees ; and 

 T. diffusa from Ceylon, on leaves. 



Pilinia and Acroblaste.* — Dr. G. B. De Toni assigns reasons for 

 suppressing the new genus of Chroolepidese Acrohlaste proposed by 

 Eeinsch. The species included under it he regards merely as the fertile 

 condition of Algae belonging to Kutzing's Pilinia, also belonging to the 

 Chroolepideee. 



Influence of Position on the Morphological Development of some 

 Siphonocladacese.t — Herr F. Noll has endeavoured to determine experi- 

 mentally whether the great development and branching of the leaf-like 

 portion of the single cell in Bryopsis muscosa and Caulerpa prolifera is 

 due to heliotropism or to geotropism. By reversing the direction of 

 growth, he found that it was invariably only on the illuminated side of 

 cut leaves that any new development of " leaf " and " stem " took place, 

 whether this illuminated side faced upwards or downwards, while the 

 "roots" were formed only on the dark side, the differentiation being 

 therefore independent of gravity. Herr Noll compares these phenomena 

 to the behaviour of soft iron towards a magnet, regarding it as a kind of 

 polarity. In the Siphonocladacese, with their continuous parietal layer 

 of protoplasm, we have plants which, like soft iron, are readily modified 

 by external factors which affect growth, and whose polarity can, 

 therefore, be easily reversed. 



Fungi. 



Toxic Principles of Fungi.J — M. G. Dupetit describes the separa- 

 tion and isolation of certain toxic principles from various fungi, and 

 also the effect produced when administered to animals. The author in 

 the first place gives a resume of the toxic principles which are already 

 known to exist in fungi. In Amanita muscaria there is a very poisonous 

 alkaloid, muscarine; A. phalloides contains a tetanic alkaloid or a 

 glucoside ; and ergot of rye contains a very poisonous alkaloid, ergotine. 

 The author then gives the results of an investigation of Boletus edulis, 

 which contains a principle capable of causing death by hypodermic 

 injection, but not if taken internally ; the juice of the Boletus, however, 

 loses its toxic properties under the influence of heat. The development 

 of microbes in the juice of the Boletus does not in any way modify its 

 toxic properties ; the active principle was also proved to be a soluble 

 poison. Contact with hydrogen or oxygen has no effect upon it, but it 

 is destroyed by ozone. Various solvents were then tried, and the toxic 

 principle was found to be insoluble in chloroform, ether, and alcohol. 



The author then gives a method for the extraction of the toxic 

 principle of Boletus, which he states possesses the principal characters 

 of a soluble ferment, and for which he proposes the name mycozymase. 



* Notarisia, iv. (1889) pp. 653-5. 



t Arbeit. Bot. Inst. Wiirzburg, iii. (1888) pp. 466-76 (2 figs.). 

 X Mem. Soc. Sci. Phvs. et Nat. Bordeaux, iii. (1887) pp. 185-215. 

 1889. ' 2 G 



