September 25, 1885.] 



SCIENCE. 



273 



numerous qualities that are not strictly measurable, 

 we must omit reference to number and proportion, 

 and frame the definition thus : ' The type is an ideal 

 form towards which the children of those who devi- 

 ate from it tend to regress.' 



The stability of a type would, I presume, be meas- 

 ured by the strength of its tendency to regress; thus 

 a mean regression from 1 in the mid-parents to f in 

 the offspiing would indicate only half as much sta- 

 bility as if it had been to ^. 



The mean regression in stature of a population is 

 easily ascertained, but I do not see much use in know- 

 ing it. It has already been stated that half the popu- 

 lation vary less than 1.7 inches from mediocrity, this 

 being what is technically known as the ' probable ' 

 deviation. The mean deviation is, by a well-known 

 theory, 1.18 times that of the probable deviation, 

 therefore in this case it is 1.9 inches. The mean 

 loss through regression is ^ of that amount, or a little 

 more than .6 inch. That is to say, taking one child 

 with another, the mean amount by which they fall 

 short of their mid-parental peculiarity of stature is 

 rather more than six-tenths of an inch. 



With respect to these and the other numerical esti- 

 mates, I wish emphatically to say, that I offer them 

 only as being serviceably approximate, though they 

 are mutually consistent; and with the desire that they 

 may be reinvestigated by the help of more abun- 

 dant and much more accurate measurements than 

 those I have had at command. There are many 

 simple and interesting relations to which I am still 

 unable to assign numerical values for lack of ade- 

 quate material, such as that to which I referred some 

 time back, of the superior influence of the father 

 over the mother on the stature of their sons and 

 daughters. 



The limits of deviation beyond which there is no 

 regression, but a new condition of equilibrium is en- 

 tered into, and a new type comes into existence, have 

 still to be explored. Let us consider how much we 

 can infer from undisputed facts of heredity regard- 

 ing the conditions amid which any form of stable 

 equilibrium, such as is implied by the word 'type,' 

 must be established, or might be disestablished and 

 superseded by another. In doing so I will follow 

 cautiously along the same path by which Darwin 

 started to construct his provisional theory of pan- 

 genesis ; but it is not in the least necessary to go so 

 far as that theory, or to entangle ourselves in any 

 questioned hypothesis. 



There can be no doubt that heredity proceeds to a 

 considerable extent, perhaps principally, in a piece- 

 meal or piebald fashion, causing the perscm of the 

 child to be to that extent a mosaic of independent 

 ancestral heritages, one part coming with more or 

 less variation from this progenitor, and another from 

 that. To express this aspect of inheritance, where 

 particle proceeds from particle, we may conveniently 

 describe it as ' particulate.' 



So far as the transmission of any feature may be 

 regarded as an example of particular inheritance, so 

 far (it seems little more than a truism to assert) the 

 element from which that feature was developed must 



have been particulate also. Therefore, wherever a 

 feature in a child was not personally jjossessed by 

 either parent, but transmitted through one of them 

 from a more distant progenitor, the element whence 

 that feature was developed must have existed in a 

 particulate, though impersonal and latent form, in 

 the body of the parent. The total heritage of that 

 parent will have included a greater variety of mate- 

 rial than was utilized in the formation of his own 

 personal structure. Only a portion of it became 

 developed : the survival of at least a small part of the 

 remainder is proved, and that of a larger part may be 

 inferred by his transmitting it to the person of his 

 child. Therefore the organized structure of each 

 individual should be viewed as the fulfilment of only 

 one out of an indefinite number of mutually exclu- 

 sive possibilities. It is the development of a single 

 sample drawn out of a group of elements. The con- 

 ditions under which each element in the sample 

 became selected are, of course, unknown ; but it is 

 reasonable to expect they would fall under one or 

 other of the following agencies: first, self-selection, 

 where each element selects its most suitable neigh- 

 bor, as in the theory of pangenesis; secondly, gen- 

 eral co-ordination, or the influence exerted on each 

 element by many or all of the remaining ones, 

 whether in its immediate neighborhood or not; 

 finally, a group of diverse agencies, alike only in the 

 fact that they are not uniformly helpful or harmful, 

 that they influence with no constant purpose: in 

 philosophical language, that they are not teleologi- 

 cal; in popular language, that they are accidents or 

 chances. Their inclusion renders it impossible to 

 predict the peculiarities of individual children, 

 though it does not prevent the prediction of average 

 results. We now see something of the general char- 

 acter of the conditions amid which the stable equi- 

 librium that characterizes each race must subsist. 



Political analogies of stability and change of type 

 abound, and are useful to fix the ideas, as I pointed 

 out some years ago. Let us take that which is af- 

 forded by the government of a colony which has be- 

 come independent. The individual colonists rank as 

 particulate representatives of families or other groups 

 in the parent country. The organized colonial 

 government ranks as the personality of the colony, 

 being its mouthpiece and executive. The govern- 

 ment is evolved amid political strife, one element 

 prevailing here, and another there. The prominent 

 victors band themselves into the nucleus of a party: 

 additions to their number, and revisions of it, ensue, 

 until a body of men are associated capable of con- 

 ducting a completely organized administration. The 

 kinship between the form of government of the col- 

 ony and that of the parent state is far from direct, 

 and resembles in a general way that which I conceive 

 to subsist between the child and his mid-parentage. 

 We should expect to find many points of resemblance 

 between the two, and many instances of great dis- 

 similarity; for our political analogy teaches us only 

 too well on what slight accidents the character of 

 the government may depend when parties are nearly 

 balanced. 



