The Problem of Inheritance
Habit and Heritage. By Frederic Wood Jones. (Kegan Paul. 5s.)
NOBODY who has ever listened to or read the work of Professor Wood Jones can have failed to recognise the spell of an outstandingly original and persuasive mind. He has studied corals in the Cocos Keeling Islands, mummies in Egypt, marsupials and birds in Australia, the human young, in the shape of students, in England, Australia, America and China ; and probably nobody has done more to burst the bounds of the dissecting-room, to interpret anatomy in terms of function, and both in a setting of life as a whole—from molecules to Milton, including common sense—than this much- travelled professor, to be found at the moment at Manchester University. In his present volume, which is written at the top of his brilliant literary form, he has challenged the theory—still held. by the great majority of his contemporaries—that acquired charac- teristics cannot be inherited. It was not, as Professor Wood Jones reminds us, held by the earlier protagonists of the theory of evolu- tion, such as Lamarck, Buffon and Erasmus Darwin. Even Charles Darwin was less whole-hearted about it than many who have not studied his actual writings have supposed. But reinforced by Weiss- mann's theory of the continuity or immortality of the germ cells— their segregation, as it were, from all the other cells of the individual bodies by which they are surrounded—this theory has held the field
for at least two generations. It is the germ plasm, with its hypo- thetical genes, that is all important. Racial modifications, if they occur, are due to fortuitous variations in this. They are not due to the habits or behaviour of individuals, even long lines of individuals, which do not—according to this theory—become part of the inborn racial inheritance.
This is a conception that, in Professor Wood Jones' view, has had an influence far beyond the lecture rooms and laboratories of the scientist. Such phrases as Darwin's " struggle for existence," Herbert Spencer's " survival of the fittest," plus this theory of the unbroken germ thread, of genes unalterable by the behaviour of the individuals who contain them, have contributed, he believes, to certain of the ideologies that we are now fighting—to a cold and, for other than herrenvolk, more or less hopeless determinism. If the theory, however, is sufficiently supported by observed facts, the scientist- out for truth may regard all this as regrettable. He cannot, for such a consideration, deny the theory.
But is this theory sufficiently supported by observed facts? Is it even plausibly tenable? As the result of a lifetime's thought and work, Professor Wood Jones answers "No " to each question. Bit by bit, with a skill that Freeman Wills Crofts and Agatha Christie might envy, he marshals his evidence in a book so easy to read— with the possible exception of Chapter IX—that for the ordinary layman it becomes as fascinating as a detective story. Some of his evidence is destructive. Some is constructive. There are the facets, for instance, to be found on the tibia bones of the Australian aborigines who, from time immemorial, have squatted in a fashion peculiar to themselves. These facets are not to be found on the tibia bones of the chair-using or non-squatting races. But they are to be found in the very young children of the Australian aborigines long before they could have come there for mechanical reasons. Again, there are the hair trends in certain fur-bearing animals— whorls and direction-trends corresponding to the particular animal's toilet habits with fore-paws or hind-paws. But these whorls and trends are to be found in the very earliest period of the growth of their young, long before any toilet actions have been undertaken.
These are but two instances quoted by Professor Wood Jones ; and if they are not examples of the ultimate blending in the racial heritage of the results of long-continued individual behaviour throughout many generations—if they are not examples, in other words, of the inheritance of acquired characteristics—how are they,. he inquires, to be more reasonably explained? The answer must of course be left to the expert. But the ordinary reader will find Professor Wood Jones' arguments very hard to resist. In any case, he will have enjoyed, when he closes the book, a mental adventure
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