THE LA W OF LIKENESS, AND ITS WORKING. 



559 



posed to be thrown off from cells at every stage 

 of the development and growth of a living be- 

 ing. More especially do they aggregate together 

 to form the germ, or the materials from which 

 the germ is formed. Transmitted thus from par- 

 ent to offspring, the latter may be regarded as 

 potentially composed of the gemmules derived 

 from its parent — which, like the organic mole- 

 cules of Buffon, are charged with reproducing in 

 the young form the characters they have acquired 

 from the parent. 



Regarded from a physiological standpoint, this 

 explanation of the transmission of likeness from 

 parent to offspring appears, it must be owned, to 

 present no difficulties of very formidable kind. Sci- 

 entific evidence regarding the functions and prop- 

 erties of cells is thoroughly in agreement with the 

 theory, as far as the behavior of these bodily units 

 is concerned. The exercise of scientific faith and 

 the weighing of probabilities commence with the 

 assumption of the development of the gemmules 

 from the cells ; and it may be asked if the belief 

 that these gemmules are capable of transmission 

 and aggregation, as held by this theory, is one in- 

 consistent with the tenets and discoveries of bio- 

 logical science at large. If we inquire regarding 

 the feasibility of the mere existence of such mi- 

 nute gemmules, we shall find that physical sci- 

 ence opposes no barrier to the favorable reception 

 of such an idea. The inconceivably minute size 

 of the particles, for example, given off from a 

 grain of musk, which scents a room for years 

 without losing so much of its substance as can be 

 determined by the most acute physical tests, lies 

 beyond the farthest limit even of the scientific im- 

 agination. The particles of vaccine lymph diffused 

 through the body by the lancet of the vaccinator, 

 are much more minute than the smallest cells ; 

 yet, judged by the standard of development and 

 by the effects of their multiplication in our frames, 

 their existence must be regarded as anything but 

 problematical. Then, as regards numbers, the 

 eggs of some animals exist in quantities of which, 

 at the best, we can only form a dim and approxi- 

 mate idea. A small parasitic worm, the Ascaris, 

 is known to produce 64,000,000 eggs, and some 

 of the orchids will produce as many seeds ; while 

 the fertility of some fishes is almost inconceivable. 

 It has been objected, it is true, to this conception 

 of the manner through which the law of likeness 

 operates, that it is difficult to believe in the com- 

 plicated powers and tendencies of the gemmules 

 to select and carry the special qualities of the 

 cells from which they originate; and that, in 

 short, the conception credits the gemmules with 



powers of too mysterious and occult a kind for 

 ordinary acceptance and belief. But, in answer 

 to this objection, it may be urged that the powers 

 with which the gemmules are credited are not a 

 whit more extraordinary than those possessed by 

 cells, or than those which nerve-cells and nerve- 

 fibres possess, for example, in forming and trans- 

 mitting the undetermined, mysterious force which, 

 under certain conditions, becomes resolved into 

 thought and mind. The mere conditions of hered- 

 ity which the theory explains, constitute, in fact, 

 a greater draft upon scientific credulity than is 

 demanded by any conditions or ideas included in 

 the explanation itself. Moreover, there is hardly 

 a condition, illustrated by the examples of hered- 

 ity and animal development already given, which 

 is insusceptible of explanation through the aid of 

 this theory. The cases of fission illustrated by 

 the fresh-water worms, and the process of budding 

 exemplified by the zoophyte, become intelligible 

 on the idea that a determination of the gemmules 

 to the parts concerned in these processes takes 

 place, and that by their aggregation they form 

 parts resembling those from which they were de- 

 rived. The curious phases of reproduction in 

 the plant-lice, in which, it will be remembered, fe- 

 male insects were seen to be capable of produc- 

 ing generation after generation of beings re- 

 sembling themselves without the intervention 

 of the opposite sex, are likewise explained by the 

 supposition that gemmules aggregate in quanti- 

 ties in the egg-producing organs of the insects. 

 These gemmules are further regarded as being 

 charged with the power of perpetuating the like- 

 ness of the stock from which they were origi- 

 nally derived, and being transmitted from one 

 generation to another, until, through some more 

 special modification, the periodical production 

 of fertilized eggs in autumn is once more illus- 

 trated. The exact nature of "alternate genera- 

 tions " of the zoophytes and salpaa becomes clear 

 to us if we presume that the gemmules of the pro- 

 ducing form, such as the zoophyte, are multiplied 

 and specially developed to form the jelly-fish-bud, 

 which, finally, as we have seen, is launched 

 abroad charged with the task of reproducing the 

 zoophyte. Each egg of the jelly-fish contains 

 thus the gemmules inherited from, and which 

 convey the likeness and form of, the zoophyte ; 

 the special development of new beings seen in 

 this case presenting a contrast to the ordinary in- 

 crease of the single zoophyte by budding. The 

 metamorphoses or changes which animals under- 

 go in passing from the egg to the adult state — 

 well illustrated by the insect-class — can similarly 



