Page:The New International Encyclopædia 1st ed. v. 09.djvu/881

* HEREDITY. 811 HEREDITY. Anothei- class of e.xceptioiis to the noniial law physical, but also mental and moral. The family of inheritance is that of reversions. When two of Jukes in New York St-ate alTorils a striking domesticated races of dissimilar <nuilitics are illustration of inheritance of crime. In fact, the crossed, the progeny are often unlike either majority of crimes against the person are done N = S NJ'=N S9 N: h h I f^c? h S? ic? I I I I Sc? iXc? Nc? N? N? S? k 1 I Sc? «c? Sc? = N N = t'c? parent, but 'hark back' to some early ancestial condition. The cause of reversion is completely unknown. It is difiicult to understand how hereditary qualities can lie so long latent; but the fact has to be recognized. Telegony. An alleged case of irregular inherit- ance is that known as "telegony," or the influence upon subsequent oft'spring of the first sire. The most famous ease is that of Lord Morton's mare. Toward the end of the last century Lord ilor- ton, an Englishman, imported some "quaggas' — in reality, Burchell's zebra. (See Zebra.) One of these was crossed with a pure-blood Arabian mare, which breeds very true, and a hybrid foal was obtained. Subsequently the Arabian mare was crossed with an Arabian horse, and the foal was marked like the hybrid. Another case was that of Mr. Giles's sow, described in the Transac- <i(yiis of the Philosophical Society (London, IS21). A black and white Essex .sow was mated with a wild boar of a deep chestnut color, and the "pigs produced partook in appearance of both boar and sow, but in some the chestnut color of the boar stronglj' prevailed" (prepotency of the ancestral race). Later the sow was mated with a boar of her own black and white race, which usually breeds very true, yet the sow produced pigs marked with the same chestnut tint as the pigs of the first litter. Dar- win (^'arin1ion of Atiimuls and Pliinix Under Dnmextiration. 1868) gives references to other cases. Belief in telegony is widespread among breeders of domestic animals, but it still lacks acceptance among scientific naturalists, chiefly because the possibility of its occurrence is hard to understand. (4) Limits of I.heritance. As we have just seen in regard to telegony, the limits in the capacity for inheritance are uncertain. But more important still is the question of the kinds of qualities which are or are not inherited. All qualities of organisms are classified as' innate and acquired. Innate characters are those determined in the fertilized egg: acquired characters are such as affect the organism from without during its development. Innate qualities are. of course, inherited. Whether acquired characters can be inherited is disputed : the whole point at issue is. What are acquired characters? (See Lam.^rck: Xeolamarckism : Use-Ikhekitance. 1 The ef- fects of nutrition, which are generally placed in the category of tlie acquired, are certainly felt in the second generation, especially among plants. But whether the education of a race for many gen- erations eventually so affects the young that they are more docile is. at the present lime, doubtful. The characters which are inherited are not only S(J S? Sc? Sc? k h I^cf by members of recognized criminal families. It would be a reasonable measure of self-defense for the State to prevent the nnirriage of criminals. The strength of inheritance is in some eases stronger than that of environment and nurture. Galton, in his history of twins, tells of identical twins, who, living far apart, fell ill of the same disease at the same time, so exactly were their bodies attuned. The Physical Basis op Heredity. Although Owen (1849), and afterwards H. Spencer (1866), and Daiwin (1868; see Pangenesis), had sug- gested that there was a physical basis of heredity, the first one to ofl'er an objective and scientific basis was Dr. G. Jiiger, who in 1870 (and more fully in 1878) thus stated his position: "Through a great series of generations the ger- minal protoplasm retains its specific properties, dividing in every reproduction into an ontoge- netic portion, out of which the individual is built up, and a phylogenetic portion, which is reserved to form the reproductive material of the mature offspring. This reservation of the phylogenetic material I described as the continuity of the germ protoplasm. Encapsule<I in the ontogenetic ma- terial the phylogenetic protoplasm is sheltered from external influence, and retains its specific
 * ind embryonic char.acters."

It should be observed that Spencer [Principles of Biology) based the ])henomena of heredity on the supposed presence of 'physiological units,' which he conceived to be immensely more com- plex th.an chemical unit-s or molecules. Darwin im.igined that the cells of the body throw off minute 'gemmules,' which are dispersed through- out the whole system. But his hypothesis wa.s experimentally disproved by Galton (1S75). Niigeli (1884) conceived that in every living cell there are an enornunis number of minute ]iar- ticles (niiccllie). These correspond to the plas- tidules of Elsherg and of Ilaeckcl, the "idioblasts' of O. Hertwig, and the 'hiophores' of Wcismann. Sedgwick Minot suggested that Nilgeli'a hypothet- ical idioplasm, which be (Niigeli) supposed to exist in every living cell, is probably identical with the nuclear chromatin of cells, and that heredity is due to the transfer from parent to offspring of this nuclear subst,ance. In 188.T were i)ublished Wcismann's essays on heredity. His view was in the line of .Tiiger's hypothesis, but greatly expanded, and with many new and original .suggestions. He pro- posed the now famous doctrine of 'the con- tinuity of the germ plasm.' .According to his view "The nature of heredity is based upon the transmission of nuclear substance with a specific nucleoplasm of the germ cell, to which 1 have