42 GENERAL SKETCH OF THE CELL 



mass as a whole, 1 and the physiological autonomy of the individual 

 cell falls into the background. It is true that the cells may acquire 

 a high degree of physiological independence in the later stages of 

 embryological development. The facts to be discussed in the eighth 

 and ninth chapters will, however, show strong reason for the conclu- 

 sion that this is a secondary result of development through which the 

 cells become, as it were, emancipated in a greater or less degree, 

 from the general control. Broadly viewed, therefore, the life of the 

 multicellular organism is to be conceived as a whole ; and the appar- 

 ently composite character, which it may exhibit, is owing to a second- 

 ary distribution of its energies among local centres of action. 2 



In this light the structural relations of tissue-cells becomes a ques- 

 tion of great interest ; for we have here to seek the means by which 

 the individual cell comes into relation with the totality of the organ- 

 ism, and by which the general equilibrium of the body is maintained. 

 It must be confessed that the results of microscopical research have 

 not thus far given a very certain answer to this question. Though 

 the tissue-cells are often apparently separated from one another by a 

 non-living intercellular substance, which may appear in the form of 

 solid walls, it is by no means certain that their organic continuity is 

 thus actually severed. Many cases are known in which division of 

 the nucleus is not followed by division of the cell-body, so that multi- 

 nuclear cells or syncytia are thus formed, consisting of a continuous 

 mass of protoplasm through which the nuclei are scattered. Heitz- 

 mann long since contended ('73), though on insufficient evidence, that 

 division is incomplete in nearly all forms of tissue, and that even when 

 cell-walls are formed they are traversed by strands of protoplasm by 

 means of which the cell-bodies remain in organic continuity. The 

 whole body was thus conceived by him as a syncytium, the cells 

 being no more than nodal points in a general reticulum, and the body 

 forming a continuous protoplasmic mass. 



This interesting view, long received with scepticism, has been in a 

 measure sustained by later researches, though it still remains sub 

 judice. Tangl, Gardiner, and many later observers have shown that 

 the cell-walls of many plant-tissues are traversed by delicate intercel- 

 lular bridges, and similar bridges have been conclusively demon- 

 strated by Bizzozero, Retzius, Flemming, Pfitzner, and many others 

 in the case of animal epithelial cells (Figs, i, 9). The same has 

 been asserted to be the case with the smooth muscle-fibres, with car- 

 tilage-cells and connective-tissue cells, and in a few cases with nerve- 

 cells. Paladino and Retzius ('89) have endeavoured to show, further, 

 that the follicle-cells of the ovary are connected by protoplasmic 



!Cf. Chapters VIII., IX. 



2 For a fuller discussion see pp. 293 and 311. 



