LAW OF ACCELERATION. 43 



being due to the law of natural selection. We do not deny the existence of 

 such examples ; we are only anxious to hear of their existence, and to be able 

 to examine the evidence. 



Weissmann J also seems to have been unacquainted with the same literature, 

 and claims the discovery of the law of acceleration for Wiirtenberger. Weiss- 

 inann's interpretations of the phenomena were in part very similar to our own. 

 He rejected Wurtenberger's theory of the origin of acceleration through the 

 action of natural selection, and states that it is due to the innate law of growth, 

 which rules every organism. In many places he explains this law of growth as 

 a mechanical law, and the origin of variations as due to the innate response of 

 the organism to external forces exciting it to suitable changes. This law of 

 variation through mechanical causation is identical with that advocated by Cope, 

 Ryder, and the author ; but with regard to this there can probably be no contro- 

 versy about priority. Dr. A. S. Packard has shown that such views are essen- 

 tially rehabilitations and improvements upon Lamarck's theory of effort, and he 

 has appropriately named us the Neo-Lamarckian school. 2 



This eminent author (Weissmann) has apparently abandoned this position in 

 his later works. He claims that the protoplasmic basis of organisms is alone 

 the vehicle of heredity, and substantially imperishable or continuous; that all 

 variations taking place in the organisms, unless they affect this basis so as to 

 modify the ovum, are not inherited ; that the variations of males and females are, 

 when inherited in the offspring, the originators of new characters through the 

 new combinations which necessarily arise, and he also regards natural selection 

 as the prime agent in the preservation and perpetuation of these variations. 3 We 

 have been unable to find any characters which were not inheritable in some series. 

 The behavior of all characteristics which have been introduced into any series 

 of species shows them to be subject to the law of acceleration, in whatever way 

 they have originated, whether primarily as adaptive characters, according to our 

 hypothesis, or by natural selection and through the combination of the sexual 

 variations, as supposed by Weissmann. All of the degenerative changes took 

 place in retrogressive series, in precisely the same way as is described above for 

 progressive changes. Thus, the degradational characters and uncoiling became 

 noticeable in the old of individuals and of species first, and then appeared, in 

 obedience to the law of acceleration of development, at earlier stages in suc- 

 ceeding or derivative forms, until finally they entirely replaced the normal 

 progressive characteristics of the nealogic stages. A straight Baculites-like modi- 

 fication could not have been produced by the unfavorable surroundings directly 

 from any close-coiled form ; it must have arisen from the intermediate arcuate 

 and crioceran modifications. If this be true, heredity must have played its part 

 even in the extreme modifications of abnormal geratologous series, however 

 improbable this may seem. 



1 Studies in the Theory of Descent, Eng. ed., transl. by Meldola, T. pp. 274, 277. 



2 Standard Natural History, edited by Kingsley, Introduction; and also Cope's " Origin of the Fittest," 

 in which see index, Lamarck. 



3 Continuit'at der Keimplasmas; also Ueber der Vererbung; see also, as in favor of the views here ad- 

 vanced, Kolliker's criticism, Karyoplasma und Vererbung, Zeit. Wissensch. Zool., XLIV., 1886. 



