September 14, 191 1] 



NATURE 



343 



shorter, and in some cases of a slighter character ; for 

 example, the excerpts from the technical journals on 

 various questions of electrical practice ; but the reader 

 who wishes to follow Lord Kelvin in his more abstract 

 speculations will find plenty of occupation in this 

 volume also. There are his papers on molecular and 

 crystalline theory, which are heroic attempts to find 

 mechanical explanations of such things as the pyro- 

 electricity and piezoelectricity of crystals, and the 

 known chemical and physical properties of gases, 

 liquids, and solid crystalline substances. 



That one man should have attacked with so much 

 success so many subjects of transcendent difficulty is 

 a great marvel. But our wonder is mingled with 

 regret that his mind should have been distracted so 

 much as it was from the great themes with which it 

 was pre-eminently fitted to deal. The turning from 

 one thing to another probably, however, did not result 

 in so much dissipation of its energy as might be 

 supposed. He obtained mental refreshment by 

 change of the objects of thought, and often when he 

 returned to the consideration of difficulties obtained 

 their solution with unexpected facility. 



The work of editing has been excellently performed 

 by Sir Joseph Larmor. He has appended notes here 

 and there, but with a reverent frugality, and in their 

 substance they are short and to the point. 



A. G. 



THE NUCLEI OF THE PROTISTA. 

 Die Konstitution dcr Protistenkerne, und ihre Bedeut- 

 ung fur die Zellenlehre. By Prof. Max Hartmann. 

 Pp. v + 54. (Jena : Gustav Fischer, 19 n.) Price 

 1.60 marks. 



THIS paper is an extended version of a lecture 

 delivered by Dr. Hartmann at the International 

 Zoological Congress in 1910. It is an attempt to 

 obtain a simple interpretation of the many complex 

 nuclear conditions recorded in the Protista. 



By "constitution" Dr. Hartmann means "morpho- 

 genetic constitution," and it appears from his paper 

 that " Protista " means— as is so usual — chiefly the 

 Protozoa. 



Dr. Hartmann 's views are not easily given or criti- 

 cised in a short space, for they contain much that is 

 purely hypothetical and highly controvertible. Ke 

 insists, in the first place, upon the universal occurrence 

 of a centriole in all protists — a contention that is not 

 likely to find universal acceptance. The cyclical 

 changes (centrifugal and centripetal streaming) under- 

 gone by this body are also insisted upon. 



Nuclei are classified as " monoenergid " and "poly- 

 energid " — " energid " being used in a sense different 

 from that of its inventor, Sachs. Monoenergid or 

 univalent nuclei (e.g. in Umax amcebae) consist of 

 two components — idio-generative (chromosomes) and 

 locomotor-generative (centrioles, polar caps, &c). The 

 power of polar division is an important attribute of 

 the locomotor component. Polyenergid nuclei (e.g. 

 those of Radiolaria) are those which are reallv not 

 simple, but multivalent, containing many individual- 

 NO. 2185, VOL. 87] 



ised univalent nuclei inside them. These are tne 

 " chromosomes " (e.g. in Aulacantha), which are reaily 

 not chromosomes but nuclei. 



Mitosis in the Protozoa is accordingly univalent or 

 multivalent, according as the nucleus is monoenergid 

 or polyenergid. From which it follows that the nuclei 

 and their mitoses are not homologous throughout the 

 Protista. There is no true amitosis in any protist — - 

 the process now so called being designated "pro- 

 mitosis." 



We are glad to see that Dr. Hartmann now rejects 

 the "box within box" trophokinetic binuclearity 

 hypothesis which he formerly advocated so strongly, 

 and now regards binuclearity— formerly of universal 

 occurrence — as exceptional in the Protista. "Genera- 

 tive chromidia " he regards as monoenergid nuclei 

 which have escaped from a polyenergid nucleus. The 

 formation of new nuclei from chromidia is therefore 

 " explained " — the nuclei are really there all the time, 

 but at last become visible. There are also numerous 

 other curious interpretations of protozoan nuclei result- 

 ing- from Dr. Hartmann 's hypothetical considerations. 

 Thus, the mitotic figure of Acanthocystis is really not 

 an ordinary mitotic figure, but a composite figure com- 

 posed of two nuclei which simulate one. It may be 

 noted, however, that the interpretation of mono- 

 energid nuclei as consisting of two components is, in 

 reality, merely a variant of Dr. Hartmann 's former 

 binuclearity hypothesis, become more complex by the 

 introduction of polyenergid nuclei. 



The relation of protozoan nuclei to metazoan nuclei 

 and the constitution of the latter, is only briefly and 

 hesitatingly considered. Dr. Hartmann thinks that 

 all the chromosomes of a univalent protozoan nucleus 

 are homologous with only one chromosome in a meta- 

 zoan nucleus. Chromosomes in the former correspond 

 with chromioles in the latter. Metazoan nuclei are, 

 for the most part, polyenergid — the chromosomes 

 being nuclei (or energids in Hartmann 's sense). 

 "Only the simple monoenergid atypical amcebae and 

 similar forms can be considered as elementary 

 organisms in the sense of the cell theory." The 

 union of the ovum and spermatozoon in Metazoa is 

 not homologous with the conjugation of two proto- 

 zoan gametes : for the latter are monoenergid, the 

 former polyenergid. 



Dr. Hartmann's ideas are discussed at some length 

 in numerous special cases in the Protozoa, with the 

 aid of figures copied from other works. There are 

 several misprints in the text, and I may point out 

 that " Herr Newin " referred to on page iS is my 

 friend and former pupil Mr. K. R. Lewin. His con- 

 clusions are at present indefinite, and do not warrant 

 what Dr. Hartmann says of them. 



Whether Dr. Hartmann's speculations will turn out 

 to be well-founded or not, future work will determine. 

 For our own part, we by no means agree with all his 

 interpretations. But they will, no doubt, give rise to 

 further discussion and analysis of a difficult problem, 

 and thereby perhaps lead eventually to a better under- 

 standing of the nuclei of the Protista. 



C. Clifford Dobell. 



