Morphologie und Teratologie. — Physiologie. 137 



■cerned, while when permanent tissue becomes secondarily 

 embryonic, structures are produced which give rise to one or 

 more new plants. In support of this is mentioned the behaviour 

 of yoLing leaves of Polypodiiim Heracleum in the first case, 

 and Begonia in the second. The character of the organs con- 

 structed depends on the condition of the plant. Among fungi 

 the investigations of others are cited. In higher plants Begonia 

 Rex affords a good example. Outside factors do not play a 

 great part in determining the character of organs formed in 

 regenerative processes. The factors which condition this are 

 the structure of the parts concerned and the direction in which 

 the constructive material is moving, while the wound Stimulus 

 must not be neglected. The paper is summed up as foliows: 



1. The vegetative points serve as centers of attraction for the 

 constructive material necessary for the formation of new organs; 



2. In an attached leaf the materials flow into the stem, while 

 in a leaf which has been detachad the materiais are 

 used by the vegetative points of the leaf itself; 3. The 

 removal of the vegetative points of the leaf is followed by 

 the transfer of the place of origin of new structures to a point 

 on the conducting tracts at the base of the leaf. 



H. M. Richards (New-York). 



KÜSTER, E., Beobachtungen über Regenerationser- 

 scheinungen an Pflanzen. (Beiheft zum Botanischen 

 Centralblatt. 1903. Band XIV. p. 316—326.) 



Verf. fand, dass sich an Keimlingen von Anagallls caerulea 

 und Linaria cymbalarla nach Dekapitation nicht Hypokotyl- 

 ständige Adventivsprosse, als normal, entwickeln, und dass an 

 isolirten Kotylidonen mancher Cucurbitaceen Adventivknospen 

 entstehen. Winkler (Tübingen). 



Aso, K., On the influence of a certain ratio between 

 lime and magnesia on the growth ofthemulberry- 

 tree. (Bulletin of the College of Agriculture. Tokyo. Vol. V. 

 No. 4.) 



Junge Maulbeerbäume wurden in Boden cultivirt, zu 

 welchem Kalk- und Magnesiasaize in verschiedenem Verhält- 

 nisse gesetzt wurden. Es ergab sich, dass die Pflanzen am 

 besten gediehen, wenn der Kalkgehalt das 2 — 3 fache des Mag- 

 nesiagehalts betrug. Loev/. 



Beijerinck, M.W. und van Delden, A., Ueber eine farblose 

 Bakterie, deren Koh 1 enstof f n a h r ung aus der 

 atmosphaerischen Luft herrührt. (Centralblatt für 

 Bakteriologie, Parasitenkunde und Infectionskrankheiten. 

 II. Bd. X. 1903. p. 34.) 



Verff. berichten über einen physiologisch höchst merk- 

 würdigen Mikroorganismus, der in rein mineralischen Lösungen, 



