. The cell; outlines of general anatomy and physiology. dially diver-gent branches. Under these circumstances the nucleus, as long asthe formative processes continue, is situated in the middle of theradiation, but after growth is finished it returns to its formerposition near to the base. Confirmatory evidence of this participation of the nucleus in theformative processes is furnished us by the examination of Fungi and Alg-a?. In the multi-nucleatedhyphae of Saprolegnia lateralbranches develop ; these are alwaysfound immediately over a nucleus,which is situated close to the cell-wall. In Vauch
. The cell; outlines of general anatomy and physiology. dially diver-gent branches. Under these circumstances the nucleus, as long asthe formative processes continue, is situated in the middle of theradiation, but after growth is finished it returns to its formerposition near to the base. Confirmatory evidence of this participation of the nucleus in theformative processes is furnished us by the examination of Fungi and Alg-a?. In the multi-nucleatedhyphae of Saprolegnia lateralbranches develop ; these are alwaysfound immediately over a nucleus,which is situated close to the cell-wall. In Vaucheria and other multi-nucleated Alga?, as in the higherplants, special growing points arepresent, at which growth chiefly oc-curs ; at each of these, immediatelyunderneath the cellulose membrane,there is an accumulation of smallnuclei, after which comes a layerof chromatophores ; in the remain- Fig. 163,-Young stellate hair of An- ? portions of the Cell the positions trietia delloidea (, . Fig. 28). of these bodies are METABOLIC CHANGES 327 Phenomena, which are still more remarkable, and which indi-cate the part played by the nuclei in the formation of the cell-wall, are to be observed during: the healinsr of wounds inVaucheria. Numerous small nuclei appear in the protoplasm,which collects round about the wound, thus approaching theupper surface, whilst the grains of chlorophyll are forced backin exactly the opposite direction. By this means the nuclei andchlorophyll grains exchange places. This observation immedi-ately refutes the objection, which might otherwise easily beraised, namely, that the nucleus or nuclei are present in thoseplaces to which the protoplasm flows in greater quantities, be-cause they are carried along by the protoplasmic stream. For, ifthis were the case, we should expect to find the chlorophyll grainsalso in the same places, since these are much smaller than thenuclei, and may even be induced to change their positions byv
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