THE GENERAL SIGNIFICANCE OF AMPHIMIXIS 217 



ribbon-like, rapidly acting nuiscular axis ; or the regular geometrically 

 constructed flinty skeleton of the Radiolarians, with their radially 

 disposed sword-like or rod-like needles and their complex interlacing 

 lattice -work shells. In the latter case the complexity of the living 

 substance becomes visible only through its product, the shell, for the 

 protoplasm itself does not show any visible intricacy, and the same is 

 true of the Coccidium whose life-history we have just been tracing, 

 for in each of its stages it seems to be of very simple organization, 

 thouo-h the succession of numerous diflerent forms shows that its 

 germ-substance must be composed of numerous determinants. 



We cannot doubt, however, that, in all unicellular organisms, 

 the protoplasm can he hardly less complicated as regards its minute 

 invisible structure, since otherwise it would be impossible that the 

 delicate vital processes which Ave observe in them should run their 

 course. In this I agree, at least in principle, with the beautiful 

 picture drawn by Ludwig Zehnder in his recent book ^ already 

 mentioned, though he reached it in quite a ditt'erent way, namely, by 

 a purely synthetic method. He made the daring attempt to build up 

 the organic world from below, starting from atoms and molecules, 

 and ascending from these to the lowest vital units, our biophors, 

 to which he attributes a tubular shape and therefore calls tistellffi. 

 He imagines the cell to be made up of a large number, perhaps millions, 

 of difterent kinds of fistell?e, of which one presides over the power of 

 turgidity, another over endosmosis, a third over contraction, a fourth 

 over the conduction of stimuli, &c., so that there results a high degree 

 of cellular complexity, a composition out of numerous kinds of 

 biophors arranged on a definite architectural plan. All this corre- 

 sponds perfectly with the views I have so long championed, and 

 which alone make the existence of a nucleus intelligible, if it is com- 

 posed — as I assume — essentially of an accumulation of determinants, 

 that is, of hereditary substances. And that such a high degree of 

 complexity of structure is not a mere fanciful picture we see 

 occasionally even in the case of unicellular organisms. Thus, for 

 instance, in Coccidium proprium, parasitic in the newt [Triton), the 

 macrogamete or egg-cell (Fig. 123, JJa) liefore fertilization by tlie 

 sperm-cell or microgamete (Fig. 123, 3Ii) surrounds itself with a caj)- 

 sule, at one pole of which a minute opening, the rnicropyle, remains 

 for the entrance of the male cell. This proves, it seems to me, that 

 this particular spot of the capsule is hereditarily determined, just as 

 much and just as definitely as the ray of the flint-skeleton of a Radio- 

 larian. But if an}^ spot of the capsule can vary by itself alone, may 

 ^ Zehnder, Die Entstehung des Lebens, Fi'eiburg-i.-Br.. 1899. 



