44 PHYSIOLOGICAL MORPHOLOGY 



nevertheless the structure of the invisibly minute parts must necessarily 

 be such as will correspond with and conform to the structure of those 

 visible to us. 



The honeycomb-like structure which Butschli has discovered in the 

 protoplasm does not exclude the possibility that in this again, if all were 

 magnified a million times, an equally complicated subordinate structure 

 might be detected. To the naked eye, parenchymatous tissue seems 

 to have a finely honeycombed appearance, and in the cells of which 

 this meshwork is composed no one would have imagined that all the 

 complicated structure revealed by the microscope was present. Even 

 if Biatschli's theory should be confirmed, and attain an equal importance 

 to the first discovery of the cellular structure in plants, we are still 

 far from an exact knowledge of the laws which govern the structural 

 arrangement of living substance. Thus, it is impossible to say de- 

 finitely whether the honeycomb-like appearance is due to the protoplasm 

 being frothy or vacuolar, only the walls of the vacuoles being living, 

 or whether the vacuoles themselves are also filled with living matter 

 (^enchylema 1 ). 



Perpetual change is necessary in order that life may be maintained, 

 for the formative and constructive powers of the protoplasm could not exist 

 were it not that changes are always taking place in it, which are so corre- 

 lated as to preserve the same general composition of the whole. Alterations 

 in the form and position of the nucleus, plastids, &c. are external signs of 

 internal disturbances of the temporary equilibrium. In the process of mitotic 

 cell-division, the nucleus undergoes marked structural modifications, while 

 similar alterations are necessitated in the invisible plasmatic elements, as 

 these grow and divide. A consideration of the microcosm of planets, stars, 

 and systems around us, will enable us to understand more clearly the 

 nature of the microcosmic protoplast. In our planetary system the same 

 groupings and conjunctions are periodically repeated. Permanent changes 

 and alterations may take place in the motion, the path., or even the condition 

 of heavenly bodies (comets, meteors, &c.) under the influence of external 

 causes 2 . To the distant observer, Sinus, mighty sun though it be, appears 

 as a fixed and constant star, just as a marching regiment, seen from 

 afar, looks like a single red dot in which the movements of the component 

 parts cannot be distinguished. In the same way, the visible protoplast 



1 These few remarks must suffice on this point. P'or further details, see the original papers by 

 Butschli, as well as of O. Hertwig, Zelle, 1893, p. 18; Zimmermann, Beihefte zum Bot. Centralbl., 



1893, Bd. in, p. 213; Klemm, Jahrb. f. wiss. Bot., 1895, Bd. xxvm, p. 685. On the foamy 

 structure of siliceous jellies, &c., Butschli, Verhandlg. d. Nalurw. Med. Vereins zu Heidelberg, 



1894, Bd. V, Heft 3. Hertwig also discusses the granular theory of Altmann. See also Puriewitsch, 

 Ber. d. Bot. Ges., 1897, p. 239. 



3 See Pfeffer, Untersuch. a. d. Bot. Inst. in Tubingen, 1886, Bd. n, p. 316. 



