Morphologie, Teratologie, Befruchtung, Cytologie. 357 



annimmt. Dieser Fall wird durch das näher beschriebene Verhalten 

 der Spatha von Richardia aethiopica , der Kelchblätter von Hellebo- 

 rus exemplifiziert. Gewöhnlicher ist es, wenn ein Organ seine assi- 

 milatorische Eigenschaft verliert um eine andere Funktion dauernd 

 anzunehmen. 



Die anatomischen Verhältnisse, die mit den vikariierenden 

 Aufgaben der Pflanzenteile zusammenhängen, sowie auch die biolo- 

 gische Bedeutung der verschiedenen Erscheinungsformen des 

 Vikariates werden eingehend berücksichtigt. 



Auch bei den Kryptogamen kommt das Vikariat, obwohl unter 

 abweichenden Formen, häufig zur Geltung. Auf einige Fälle macht 

 Verf. kurz aufmerksam. Grevillius (Kempen a. Rh.). 



Minchin, E. A., On protoplasm, (Proc. Linn. Soc. Lond. 1909 — 

 1910. p. 79—83. 1910.) 



The living substance, protoplasm, in its simplest form consists 

 of two Chief constituent parts, cytoplasm and chromatin. Chromatin 

 cannot be defined solely by chemico-physical tests: it is essentially 

 a biological conception. By chromatin we understand certain grains 

 of substance embedded in the cj^toplasm, or aggregated in the 

 nucleus, and playing a definite role in the life cycle of the organism. 



The question arises, whether the cytoplasm or the chromatin 

 is to be regarded as the primary living substance. The author con- 

 cludes that chromatin is the primary living substance, — not cy- 

 toplasm. The grounds for this conclusion are as follows: 



I. No living organism is known with certaint)' which does not 

 contain substance of the nature of chromatin. Some of the minutest 

 organisms, e.g. some Bacteria and Spirochaetes, seem to consist of 

 chromatin alone. 



II. By experiment it is found that cells, if deprived of the 

 nucleus and reduced to cytoplasm alone, cannot continue living for 

 long, and cannot initiate vital changes or processes. 



III. The present State of our knowledge tends to establish as a 

 general truth that the chromatin Clements are the governing and 

 directing bodies of cells, and as such are the bearers of hereditär}'" 

 qualities. Agnes Arber (Cambridge). 



Starr, A. M., The Microsporophvlls of Ginkgo. (Bot. Gaz. IL. 

 p. 51—55. PI. 7. 1910.) 



In the development of the microsporangiate strobilus the spo- 

 rophylls appear first at the base and proceed toward the apex. The 

 development of the microsporarigium resembles that of cycads. 



Particular attention is given to the development of mucilage 

 ducts in the hump of the microsporophyll and it is found that, in 

 general, the early development is like that of sporogenous tissue 

 but later this tissue breaks down and thus the mucilage cavit}^ is 

 formed. This origin of mucilage ducts in the hump may indicate 

 that the microsporophylls of Ginkgo may have come from a peltate 

 type like the microsporophylls of Taxus. This would agree with the 

 Claim that the resin cavities in the microsporophyll of Torreya owe 

 their origin to abortive sporangia. 



Charles J. Chamberlain (Chicago). 



