I have only to add here that several years ago I wrote to Weismann drawing his attention to some facts I had observed which seemed to me to be instances of use-inheritance, and I received a reply in polite but brief and Prussian terms to the effect that the facts referred to must be capable of some other interpreta­tion, for the machinery for their transmission did not exist.

Each of these twelve quotations from Weismann’s essay is important from the present point of view, and shows how far neo-Darwinians are likely to promote the greater glory of Darwin, and though more than a quarter of a century elapsed between this essay and his death Weismann was not the man to have repudiated any of these strong statements.

Lighthouse Value.

I hope at this point a small digression is not out of place in order to introduce an aspect of Weismann’s work which is not usually appreciated. A child is aware of the great and lesser lights that rule the day and night, but for modern man these are not sufficient. Accordingly he has invented from immemorial times his oil lamps, rushlights, tallow and wax candles, gas and electric light for the illumina­tion of his streets and houses. Prehistoric man did not seem to need them, as he thought. These useful examples of applied knowledge were obviously brought into use for showing man better where he was going and where to go, what he was doing and what he wished to see. I hope this trite remark may be pardoned, for there is another form of light which suits my purpose of illustrating the aspect of Weismannism referred to above, that is the light of a lighthouse. The ancients in their crude way saw the need for this and as far back as the days of Ptolemy II. a tower to give light was erected on the island of Pharus, off the Egyptian coast, and it was called a pharos. Man found it necessary, as naviga­tion and seafaring advanced, to use this principle more and more, and on headland, sandbank and rugged coast has built noble structures to aid the sailor in his dangerous course. The oldest and finest of these in Great Britain is the Eddystone lighthouse, built first in 1695 by Winstanley and finally by Smeaton in 1756–9. For what reason is a lighthouse built and placed where it is? For the precisely opposite reason to that of the domestic candle. While this shows you where to go and how better to do your immediate business, a lighthouse is for the main purpose of showing a mariner where he should not go. It has no relation to adornment or pleasure. It does not invite you to come in your vessel and admire it. It tells you to go away and avoid the sunken rock or treacherous sands.

I submit here the sugges­tion with all deference, that the final work of Weismann has lighthouse value of a high order, as to the modus operandi of evolution. His greatness as a biologist, his candour and skill in dialectics, have built up a veritable lighthouse which may usefully warn the seeker after the path of evolution that he must turn elsewhere if he would not founder upon a reef of facts.

The two great contributions to evolutionary thought that Weismann has made should be considered separately, the theory of germ-plasm and that of evolution, though the latter seems to be the necessary outcome of the former. But the truth of Weismann’s view of heredity does not of necessity require the error of his theory of evolution.

Romanes on Weismann.

For this study the examina­tion of Weismannism by Romanes published in 1893 is of great value. I need only refer here to the main conclusions of that lucid and learned examina­tion.

Weismann’s work on the germ-plasm in pursuance of a theory of heredity is pronounced by Romanes to have remained up to 1893 substantially unaltered, though largely added to in matters of detail, and at the present time as far as I gather from a study of the more recent literature this theory holds the field or at least a commanding position in it.[26] Originally he held that the germ-plasm possessed perpetual continuity since the first origin of life, and absolute stability since the first origin of sexual propaga­tion, but he has shown himself willing to surrender the first postulate, and has himself altered the second. As it stands now it must be admitted that the continuity of the germ-plasm is an interrupted continuity with the appearance of every inherited change; the continuity is theoretical, not actual, and the stability of the germ-plasm is not absolute but of a high degree. We can thus see in the story of this original theory of heredity the lighthouse value of the pharos of Ptolemy II.