. The cell; outlines of general anatomy and physiology. and ganglion cells, etc.), Flemming observed inthe protoplasm (Fig. 6) the presence of extremely delicate threadswhich have somewhat greater refractive power than the inter-vening ground substance. These threads vary in length, beinglonger in some cells than in others: sometimes larger numbers arepresent than at others. It seemed im-possible to determine with certaintywhether they are separated from oneanother all along their length, orwhether they join together to form anet; if they do form a net, then itsmeshes must be very uneven in si
. The cell; outlines of general anatomy and physiology. and ganglion cells, etc.), Flemming observed inthe protoplasm (Fig. 6) the presence of extremely delicate threadswhich have somewhat greater refractive power than the inter-vening ground substance. These threads vary in length, beinglonger in some cells than in others: sometimes larger numbers arepresent than at others. It seemed im-possible to determine with certaintywhether they are separated from oneanother all along their length, orwhether they join together to form anet; if they do form a net, then itsmeshes must be very uneven in Flemming considers that twodifferent substances occur in proto-plasm, a thread substance and an inter-stitial substance, or a filamentous and aninterfilamentous substance (mitome andparamitome) ; upon the chemical nature of these substances andupon their general condition Flemming does not enlarge. Howmuch importance should be attached to this structure, aboutwhich at present nothing further can be stated, it remains for thefuture to Fig. 6.—Living cartilage cell ofa Salamander larva, much mag-nified, with clearly marked fila-mentous substance : after Flem-ming (from Hatschek, Fig. 2). In this section, On the Structure of Protoplasm, the ray-like arrangement ofthe protoplasm which is observed at certain stages of the division of thenucleus, or the striated appearance which is exhibited by the protoplasm ofsecretory cells, might be more fully described. Since, however, such structuresonly occur under special conditions, it has been considered more advisable todefer their consideration to a later period. Fourthly, and finally, come the attempts of Altmann (II. 1) to 24 THE CELL demonstrate a still more minute structure of protoplasm (granulatheory). By means of a special method of treatment, this in-vestigator has succeeded in rendering minute particles visible inthe body of the cell; these he calls granula. He preserves theorgan in a mixture of 5 per cent, so
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