458 



NATURE 



[September io, 1903 



Nevertheless, the circumstantial evidence in favour of the 

 truth of this impression is, to my mind, so strong that we 

 are justified in considering its bearing upon the general 

 question. It is quite impossible for me on this occasion 

 to set before you at all adequately the general nature of 

 this circumstantial evidence. To do so would involve state- 

 ments concerning the actual variations of a large number 

 of species already observed in one locality and in several 

 widely distributed localities, with a discussion of the possible 

 direct influence of the conditions of such localities, so far 

 as they are known, upon each of the principal variations. 

 Such statements would necessarily be of such a special and 

 technical kind that, even if time permitted me to make 

 them, they would not be suitable for an Address of this 

 character. I may be permitted to say, however, that I am 

 collecting and preparing the evidence for publication on 

 this point at a later date. There can be no doubt, however, 

 from the evidence I have already submitted to you in part, 

 that some species are far more influenced by changes in the 

 environment, or, to simplify the expression, are far more 

 plastic than others ; and we may conclude that in the evolu- 

 tion of other groups of animals the earlier forms were far 

 more plastic than their modern descendants. In the earlier 

 stages of evolution there must have been in the first instance 

 a lessening of the power of change in structure according 

 to change of environment. The fixity or rigidity of certain 

 characters thus produced enabled a more elaborate co- 

 ordination both in form and action to occur between one 

 set of organs and another. It permitted a further localisa- 

 tion and specialisation of functions, or, in other words, 

 further differentiation of the animal tissues. 



Accompanying this differentiation there was a loss in the 

 power of regeneration. As Trembley showed many years 

 ago, a Hydra can be cut into many pieces, and each by 

 the regeneration of the parts that are missing will give 

 rise to a complete individual. The Earthworm can, when 

 cut in half, regenerate a new tail but not a new head 

 region. An Arthropod dies when cut in half, but has the 

 power of regenerating new appendages in place of those 

 that are lost. But in Vertebrates there is very little power 

 of regenerating new appendages, and the general powers 

 of regenerating new parts are reduced to a minimum. 



Now, whether the loss in the plasticity of characters was 

 the cause of the loss in the power of regeneration of lost 

 parts, or the loss in the powers of regeneration was the 

 cause of the loss of plasticity, is a problem upon which I 

 do not feel we are competent to express a definite opinion ; 

 but that the two series of phenomena are intimately associ- 

 ated is, I believe, a generalisation that is worth a good 

 deal of further thought and study. 



In Vertebrates, however, although the power of regener- 

 ation of lost parts is at a minimum, it is not by any means 

 entirely wanting. The muscles, nerves, epithelia, and other 

 tissues, are able to repair injuries caused by accident and 

 disease. And similarly, although the power of response of 

 various organs to the changes of external conditions in 

 Vertebrates is very much diminished as compared with that 

 in the lower groups of the animal kingdom, it still remains 

 in an appreciable degree. Whether the curves of variation 

 of the so-called fluctuating characters of Vertebrates re- 

 present simply or solely the influence of the environment 

 on the organism cannot at present be determined with any 

 degree of certainty ; but it appears to me that zoological 

 evidence, confirmed as it is in such a remarkable wav by 

 the recent researches of the botanists, points very strongly to 

 the conclusion that the major part of each such curve is, after 

 all, but an expression of the influence of the environment. 

 In venturing to put before you these considerations, I am 

 quite conscious of the vastness and complexity of the 

 problems involved and of the many omissions and imperfec- 

 tions which a short Address of this kind must contain. Not 

 the least of these omissions is that of any reference to the 

 distinction that might be drawn between continuous and 

 discontinuous variations in the simpler forms of life. This 

 is a matter, however, which involves so many interesting 

 and important questions that I have felt it to be beyond the 

 scope of my Address to-day. 



We are still in need of further systematic knowledge of 

 the widely distributed species of Coelenterates ; we want to 

 be able to form a more definite opinion than we can at 

 present upon the value of specific distinctions, and we need 



NO. 1767, VOL. 68] 



still further observations and descriptions of the phenomena 

 of irregular facies, abnormal growths, and meristic vari- 

 ations. But more important still is the need of further 

 researches in the field of experimental morphology. 



When we have accumulated further knowledge on these 

 jines in a group of animals such as the Coelenterata, of 

 relatively simple organisation, we shall be in a better posi- 

 tion than we are now to deal with the problems of heredity 

 and variation in the far more complicated groups of 

 Arthropoda and Vertebrates. 



NOTES. 



The following committee has been appointed by the Lord 

 President of the Council to make a preliminary inquiry into 

 allegations that have been made concerning the physical 

 deterioration of certain classes of the population : — Mr. 

 Almeric W. FitzRoy, C.V.O. (chairman). Colonel G. M. 

 Fox, C.B., Mr. J. G. Legge, Mr. H. M. Lindsell, Colonel 

 George T. Onslow, C.B., Mr. John Struthers, C.B., Dr. 

 J. F. W. Tatham. 



Writing to the Times, the honorary treasurer of the 

 Cancer Research Fund states that Mr. William Waldorf 

 Astor has just sent a cheque for 2o,oooZ. to the fund, and 

 that, as a result of the speech delivered on July 30 by Mr. 

 Balfour, several other donations have also been received ; he 

 points out, however, that the fund is still more than 25,000?. 

 short of the amount required, and appeals.for further help. 

 The address of the fund is the Examination Hall, Victoria 

 Embankment, W.C. 



The Paris correspondent of the Morning Post states that 

 particulars of a new anti-tuberculosis serum will shortly 

 be communicated to the Academy of Medicine by the dis- 

 coverer. Dr. Marmorck, of the Pasteur Institute. The 

 new serum is said to have been tried in the Paris hospitals, 

 and to have cured several comparatively advanced cases of 

 tuberculosis. 



Commander Pearv has been granted three years' leave of 

 absence by the U.S. Navy Department to enable him to make 

 another attempt to reach the North Pole. According to 

 Reuter he will start by about July i next year, in a new 

 steamer, for the Whale Sound region, where he will embark 

 a number of Eskimos and establish a permanent base at 

 Cape Sabine ; thence he will force his way to Grant Land, 

 where he hopes to establish his winter quarters on the 

 northern shore. In the following February, with the earliest 

 light, a start will be made due north over the pack ice with 

 a small, lightly equipped party, which will be followed by a 

 larger party. Commander Peary hopes to reach the Pole 

 and return to his winter quarters within little more than 100 

 days. The distinctive features of the plan are the use of 

 sledges with comparatively light loads drawn by dogs, the 

 adoption of Eskimo methods and customs, and the fullest 

 possible utilisation of the Eskimos themselves. 



Reuter's Agency learns that Major Powell-Cotton, who 

 has been exploring in Africa for the past year, arrived safely 

 at Wadelai, on the Upper Nile, in the middle of July, from 

 Mount Elgon, where he had been studying the cave-dwellers. 

 Major Powell-Cotton had had satisfactory interviews with 

 the Congo ofTicials, and was then preparing to start on an 

 expedition in search of okapi. 



A telegram from Mombasa on Saturday last states that 

 Lieut. -Col. Bruce, who, with Dr. Nabarro, was despatched 

 from London in February last, on behalf of the Government 

 and the Royal Society, to study the sleeping sickness in 

 Uganda, has left for England on the conclusion of his 

 mission. Lieut. -Col. Bruce is reported to have stated that 

 the ravages of the disease are unabated. 



