AS THE ELEMENTAL GERM OF AN ORGANISM 343 



micella of crystalline construction composed of several molecules. 

 Its absolute weight is the trillion th part of 3'53 mg. The specific 

 weight of dry albumen is 1*344. Hence, 1 cubic micro-millimetre 

 contains about 400 million micellae. Nageli, basing his calculations 

 on some further hypotheses, considers that the volume of such a 

 micella is '0000000021 cub. mic. mil. Further, upon the supposi- 

 tion that micellae are prismatic, and are only separated from one 

 another by two layers of molecules of water, 25,000 micellae would 

 occupy a superficial area of '1 sq. rnic. mil. Hence, in a body of 

 the size of a spermatozoon there would be room for a considerable 

 number of micellae, united together in groups. Thus, no difficul- 

 ties present themselves on this point. 



Logically thought out ideas are especially valuable, when they 

 harmonize with perceptible facts. The following observations are 

 in support of the above-mentioned hypothesis, i.e. that idioblasts 

 multiply by growth and sub-division ; the capacity of self-division , 

 does not only apply to the individual cell as an elementary organ- 

 ism, but also to the above-mentioned masses of special material, 

 which are enclosed in the cell. Chlorophyll, starch, and pig- 

 ment formers multiply by direct division ; the centrosomes, which 

 are only just perceptible with the microscope, also divide, when 

 nuclear segmentation occurs ; the nuclear segments split up longi- 

 tudinally into daughter-segments, and this is attributed by many 

 to the presence in the mother-thread of qualitatively different 

 units (mother-granules), which are arranged in a row one behind 

 the other; each of these is supposed to divide directly into two, 

 after which the daughter-granules thus obtained, distribute them- 

 selves evenly amongst the daughter-segments. 



Even if the idioblasts, which we have supposed to be of a much 

 smaller size, do not themselves take part in these divisions, we may 

 assume that groups of idioblasts are so concerned; the importance 

 of these observations, as concerns our theory, consists in this, that 

 they teach us how small masses of material grow in the cell by 

 themselves, and are able to multiply by division. 



Finally, another aspect of this theory may be mentioned here. 

 If the elemental germs, taken in the aggregate, give rise to a 

 definite organism, the individual constituents must evolve in 

 regular sequence, during the process of development. As sentences, 

 with logical meanings, are formed of words, and these of letters ; ' 

 and similarly, as harmonies, and whole musical compositions, 

 consist of individual notes, suitably arranged, so we must also' 



