246 



EARDWICKE'S SCIENCE-GOSSIP. 



variability (adaptation) is due to the action of environ- 

 mental chance forces upon the movement thus trans- 

 mitted, altering its character in a greater or a less 

 degree. But, supposing our knowledge of molecular 

 movement was au fait, how many distinct kinds of 

 movements of molecules would the modern physicist 

 be prepared to admit ? More than one ? 



Naegeli, on the other hand, considers protoplasm 

 to be compounded of a fluid hygroplasm and a solid 

 stereoplasm. The seat of active change is resident 

 in a portion of the latter which he terms idioplasm, and 

 which depends upon a more (higher animals) or less 

 (lower animals) complex grouping of minute particles 

 or micella2. Each cell of the body contains its own 

 portion and its own kind of idioplasm, the difference 

 between the various kinds being of a dynamical 

 character ; reproductive idioplasm is idioplasm in its 

 most primitive character, that of the germ from 

 whence the organism sprang. It is somatic, or body- 

 idioplasm which has become rendered into its primi- 

 tive condition. Then, if from two organisms engaged 

 in coitus, an equal transmission of idioplasm obtains, 

 then the future organism has characters in equal 

 degree of father and mother ; if the greater amount 

 of transmitted idioplasm belongs to the father, then 

 the future organism has characters more like its 

 father, and so on. And, since somatic idioplasm of 

 an organism is acted upon by environmental con- 

 ditions, the rendering of this kind of idioplasm to its 

 primitive state of germ idioplasm in that organism is 

 not always exact, and thus it may be conceded that 

 an organism to which it gives birth may resemble its 

 parents in not all degrees, and hence arises variability. 

 Of course, if we may regard this theory of Naegeli's 

 as not too conjectural, and there is plenty of evidence 

 to substantiate the theory of the existence of idioplasm 

 (pathological, zoological, and botanical evidence), 

 then [Simroth's laws of the colouration of Styrian 

 Limaces* may be explained as different environmental 

 conditions acting upon the somatic idioplasms of the 

 various slugs localised in the regions he enumerates ; 

 and primarily of their parents. These laws are 

 summed up as follows : — 



" I. The further north, the simpler the markings, so 

 far as black is concerned. 



2. Mountains are more favourable to brilliant 

 colouring than the plains. 



3. In the north the red of youth is extinguished in 

 the winter, in the south it is retained and further 

 developed in the summer. 



4. In mountains and in the south the colour of youth 

 is retained longer than in the plains and in the north. 



5. The full development of a red and black 

 colouring takes place only in the Southern Alps." 



To the same cause must be accorded Cockerell's 

 observation f that on the plains Limax arhorum is 



* "Steierische Nacktschnecken." Nachr. Mai. Ges, xviii. 

 pp. 65-80. 



t '^ Limax arhorunt and the Influence of Altitude on 

 Colour." Zool. (3), X. p. 341. 



spotted with black, while on the hills it is normally 

 coloured ; the variation in Limnaa, attributed by 

 Dodd * to alternating conditions of dryness and wet- 

 ness ; the albinism which Hartmann f refers to cold, 

 wetness of weather, and want of sunshine, etc. It 

 may be worth mentioning here that Gredler considers 

 albino varieties as due to heredity % ; that Eimer § is 

 of opinion that [species originate from varieties 

 produced by constitutional causes ; and that Hyatt, 

 in a paper entitled "Transformations of Planorbis 

 at Steinheim, with Remarks on the effects of gravity 

 upon the forms of Shells and Animals," which was 

 read^ before the twenty-ninth meeting of the Ameri- 

 can Association at Boston in 1880, attributes the 

 unsymmetrical spirality of gastropod shells to heredity 

 combined with the influence of gravity. 



Strasburger 11 has identified the idioplasm of Naegeli 

 with the chromatin filament of the cell-nucleus, and 

 he calls it nucleoplasm or nucleohyaloplasm. This 

 nucleoplasm directs all the metabolic processes in 

 the cells of the animal body, and he considers that 

 the filament is composed of segmented portions which 

 belong to preceding generations, and that any one 

 special segment may influence the cell protoplasm 

 (kytoplasm) of the ovum so as to give rise to here- 

 ditary qualities of the special generation from which 

 it is derived. But here — as hinted by Dr. McKendrick, 

 in the recent edition of his ' ' Text-book of Physio- 

 logy " — Strasburger " passes entirely into the region 

 of theory," and it is here that the researches of Van 

 Beneden come directly to our aid. For, "if it be the 

 case that the chromatin filaments from the male and 

 those from the female remain distinct, and are com- 

 municated in equal amounts to the nuclei formed by 

 the division of the fecundation nucleus, and if this 

 process be multiplied indefinitely in the formation of 

 the cells of the body, we see that each cell is re- 

 presentative of both father and mother to a greater 

 or less extent, according to the amount of maternal 

 and paternal idioplasm present." It is also assumed 

 that this idioplasm can increase itself in quantity by 

 nutrition, and that it can be acted upon by environ- 

 mental conditions in an amount as to'individualise the 

 organism in which such changes take place. The 

 time comes, however, in the life of the organism 

 when the cells of the body no longer proliferate and 

 the character of the organism becomes fixed. Stras- 

 burger {loc. cit.) remarks that the generative power 

 of a cell is dependent upon it being in the embryonic 

 state, and it is also said that the extrusion of the polar 

 bodies and of the seminal globule marks the return 

 of the ovum and of the spermatozoon respectively 



• " Journal of Conchology," iv. p. 304. 



t "Gastropoden d. Schweiz," 1840-44, p. xvii. In these 

 environmental conditions as producing albinism, given by 

 Hartmann, P. Hesse coincides, from observation of albino cases 

 found by him on Mt. Wittekind, Westphalia. 



+ " Nachr. Mai. Ges.," 1878, pp. 33-37-" 



5 " Tag. Deut. Nat. Vers.," Iviii. p. 408. 



II "Neue Untersuchungen fiber den Befruchtungsvorgang 

 bei den Phanerogamen als Grundlage fiir eine Theorie der 

 Zeugung." Jena, 1884. 



