jVA ture 



[November i6. 189; 



Weismann retains the original conception. But 

 the germ-plasm is now a particulate substance, and 

 inequalities of nutritioti affecting the separate elements 

 cause variations in it. The original conception has now 

 become more definite, and this increase in definition has 

 effected a reconciliation with some strong objections to 

 the generalised idea. It seems to me extraordinary that 

 a critic so acute as Dr. Romanes, not in the heat 

 ^^ controversy but in a deliberate book, should call this 

 "reuioving stone by stone, his doctrine of descent," and 

 " turning upside down the fundamental postulate." In 

 order to reach such a view he has had to be much more 

 certain than Weismann, about what Weismann meant, 

 and to attribute to "mere carelessness" the inclusion in 

 Weismann's earlier writings of indications pointing in 

 this direction. 



In Appendix I. the germ-plasm is discussed specially 

 in so far as Weismann considers pangenesis a less con- 

 ceivable and a more formal explanation. I think the 

 key to the criticism is again to be found in a misconcep- 

 tion by Dr. Romanes. He quotes from Weismann : — 



" How can such a process {i.e. the passage of gem- 

 mules into growing germ-cells) be conceivable when 

 the colony becomes more complex, when the number of 

 somatic cells becomes so large that they surround the 

 reproductive cells with many layers, and when, at the 

 same time, by an increasing division of labour, a great 

 number of different tissues and cells are produced, all of 

 which must originate de ftovo from a single reproductive 

 cell.?" 



He goes on : — 



"Here again the obvious answer is that no one has 

 ever propounded such a statement. Far from supposing 

 that ' all the different cells and tissues of a complex 

 organism must originate de novo from a single repro- 

 ductive cell,' the theory of pangenesis supposes the very 

 contrary — viz. that somatic changes in the past history 

 of the phyla had not thus originated in any reproductive 

 cell. The idea of somatic changes originating in repro- 

 ductive cells belongs to the theory of genn-plasm; but 

 even this theory does not suppose all the great number 

 of different cells and tissues which compose a complex 

 organism to have ever originated de novo from a single 

 reproductive cell.'' 



What Weismann means seems clear enough, although 

 it is dark to Dr. Romanes. The whole of a complex 

 organism grows out from an ovum, and this origin 

 occurs de novo in each generation. Pangenesis supposes 

 that gemmules from each cell in the body somehow come 

 together to form the ovum, and they come together so 

 that they unroll in proper order. For this process there 

 is no trace or shadow of evidence : to many it seems 

 a priori inconceivable. 



According to Weismann's theory the germ-plasm has 

 been slowly built up in phylogeny, and slowly unrolls in 

 the individual development. On any supposition the 

 process is wonderful : on Weismann's hypothesis the 

 evolution of germ-plasm has actually followed the evo- 

 lucion of living things from simple to complex, and there 

 is no new wonder in its complexity, nor is the unrolling 

 of the historically elaborated germ-plasm more wonderful 

 than the actual development of the historically elaborated 

 soma. The hypothesis of pangenesis supposes that in 

 each living organism there is a new wonder, the giving 

 oft" of gemmules, and their building up into an ovum 

 NO. T255, VOL. 49] 



which reproduces not only the structures which gave oft" 

 gemmules, but many an embryonic structure dating far 

 back in phylogenetic history. 



Appendix II. deals with Telegony, and practically con- 

 sists of Dr. Romanes' recent controversy with Herbert 

 'Spencer. In the mass of confused data about this sub- 

 ject it seems fairly established that at least it is very 

 rare. The influence of a first sire does not as a rule 

 affect children to a second sire. Herbert Spencer thinks 

 that the established cases are fatal to Weismann's theory, 

 inasmuch as they prove that influences impressed on the 

 soma can be transferred to the offspring. Romanes 

 thinks that they are not fatal, inasmuch as germ-plasm 

 from spermatozoa of the first sire coming in contact with 

 the ovary when a spermatozoon caused impregnation, 

 might, as they disintegrate, allow some of their germ- 

 plasm to penetrate the ovary and reach other ova. The 

 actual explanation seems, to the present writer, a much 

 simpler one, but as he is collecting facts he will only 

 mention it. In the best established cases, as for in- 

 stance Lord Morton's mare, and the sow quoted by Mr, 

 Spencer, the first sire was of a more ancestral type than 

 the second sire, and the characters in the progeny attri- 

 buted to the influence of the first sire were atavistic, and 

 in ordinary cases would have been simply referred to as 

 throw-bapks. But as at present Dr. Romanes' criticism 

 of Weismann is the matter in hand, it is enough simply 

 to point out that in this most difficult case for followers 

 of Weismann, Saul also is among the prophets — Dr. 

 Romanes agrees with Weismann ! P. C. M. 



EXTRA-TROPICAL ORCHIDS. 



Icones Orchideariuji Anstro-Africanaruni Extra-tropi- 

 cnrtivi ; or Figures, ivith Descriptions of extra-tropical 

 SoutJi African Orchids. By Harry Bolus, F.L.S. 

 Vol. i. Part i. (London : William Wesley and Son.) 

 'T^'HIS is an excellent work, devoted to the orchids 

 -L of extra-tropical South Africa, and arranged on 

 the lines of the " Refugium Botanicum" of Mr. Wil- 

 son Saunders. The first part includes fifty plates, 

 containing figures and dissections (partly coloured) 

 of fifty-one species. The text comprises descrip- 

 tions in Latin and English, references to original 

 descriptions, synonymy, geographical distributicn, 

 with critical and explanatory notes. The author's many 

 years of careful study of South African orchids, as 

 well as his previous writings on the subject, are sufficient 

 guarantee of the quality of the work ; and as regards the 

 plates, a decided improvement is noticeable, both in the 

 drawings and lithography, as compared with his previous 

 " Orchids of the Cape Peninsula" (reviewed in Nature, 

 vol. xxxix. p. 222). The work will be of great use to the 

 systematic botanist, for, as Mr. Bolus has well pointed 

 out, i^w orders of plants stand more in need of illustra- 

 tion from living specimens than orchids, because of the 

 high degree of specialisation of many of the parts, some 

 of which are very fleshy, and seldom recover their shape 

 after soaking or boiling. Nine new species are described 

 in the present part, Angrcecuni caffrum, A. Maudce, 

 Habenaria Galpini, Satyriiiin Guthriei, S. ocellatiiin, 

 PacJiites Bodkini, Disa sabulosa, D. cotiferta, and Bro'iun 



