ITS CHEM1C0-PHYSICAL AND MORPHOLOGICAL PROPERTIES 



23 



not likely to meet with much support. For on many accounts it 

 seems to be true that the structural elements of protoplasm, 

 whether they form the threads of a net, or the lamella? of a honey- 

 comb, or granules, or what not, must be solid in their nature. 

 Protoplasm does not consist of two non-miscible fluids, such as 

 water and oil, but of a combination of solid organic particles with 

 a large quantity of water. Hence quite different physical condi- 

 tions are necessarily present. (Compare section on molecular 

 structure, p. 58.) 



The third of the above-mentioned views, or the filament theory, is 

 connected with the name of Flemming (II. 10). 



Whilst examining a large number of living cells (cartilage, liver, 

 connective tissue, and ganglion cells, etc.), Flemming observed in 

 the protoplasm (Fig. 6) the presence of extremely delicate threads 

 which have somewhat greater refractive power than the inter- 

 vening ground substance. These threads vary in length, being 

 longer in some cells than in others : sometimes larger numbers are 

 present than at others. It seemed im- 

 possible to determine with certainty 

 whether they are separated from one 

 another all along their length, or 

 whether they join together to form a 

 net ; if they do form a net, then its 

 meshes must be very uneven in size. 

 Hence Flemming considers that two 

 different substances occur in proto- 

 plasm, a thread substance and an inter- 

 stitial substance, or a filamentous and an 

 interfilamentous substance (mitome and 

 paramitome) ; upon the chemical nature of these substances and 

 upon their general condition Flemming does not enlarge. How 

 much importance should be attached to this structure, about 

 which at present nothing further can be stated, it remains for the 

 future to reveal. 



Fig. 6. Living cartilage cell of 

 a 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 of 

 the protoplasm which is observed at certain stages of the division of the 

 nucleus, or the striated appearance which is exhibited by the protoplasm of 

 secretory cells, might be more fully described. Since, however, such structures 

 only occur under special conditions, it has been considered more advisable to 

 defer their consideration to a later period. 



Fourthly, and finally, come the attempts of Altmann (II. 1) to 



