oj .? i!ds*M1 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

 Of Nature trusts the mind which builds for aye.' — ^Wordsworth. 



THURSDAY, MARCH 3, 1910. 



N EXCYCLOP.EDIC TREATISE ON THE 



PROTOZOA, 

 ehrhuch der Protozoenkunde. Zweite Auflage der 

 "Protozoen als Parasiten und Krankheitserreger." 

 By Dr. F. Doflein. Pp. X4-914; 825 figures. (Jena : 

 Gustav Fischer, 1909.) Price 24 marks (unbound). 



rHE study of the Protozoa has made verA" great 

 progress during the last twenty years, so great 

 •ven those who devote themselves to this branch 

 owledge have the utmost difficult}- in keeping 

 with its rapid advance. This state of things is 

 hiefly to the great practical importance of the 

 zoa for medical, veterinary', and agricultural 

 e, but also because the primitive forms of life 

 the clue to many biological problems of funda- 

 .1 importance. Hence the number of those who 

 y themselves with researches upon Protozoa has 

 much increased, both amongst professed zoolo- 

 and also amongst those to whom zoological 

 ;ons are a secondary consideration; all such 

 rs, however, whatever their aims, will welcome 

 iblication of Prof. Doflein 's treatise. This work 

 :ensibly the second edition of his well-known 

 al on the Protozoa as parasites and causes of 

 -e, a most useful book in its time, though now 

 •-hind b\- the flowing tide of research ; its parent- 

 however, is scarcely recognisable, since the 

 i edition appears with new title, changed form, 

 ^reath- enlarged scope. The treatment of para- 

 and disease, though not neglected, takes a 

 dary place, and the work has become an ex- 

 iustive general treatise on the Protozoa. 

 It is difficult, within the limits of space imposed 

 :>on a reviewer, to give an adequate account of the 

 > -lUh of facts, ideas, and illustrations contained in 

 .00 or so pages of this book. The work is 

 ^lued into two halves, the first containing a general 

 ■count of the natural history of the Protozoa, the 

 .•cond a more detailed systematic description of the 

 iToups of Protozoa and of the special problems con- 

 d with them. 

 NO. 2105, VOL. 83] 



The general part begins with a short introduction 

 giving the definition and distinctive characters of the 

 Protozoa, and is then subdivided under the headings 

 morpholog}-, physiology, reproduction, biology (or 

 bionomics), system, and technique. The Protozoa are 

 regarded as unicellular organisms occupying a middle 

 position between the Bacteria and their allies below 

 and the Metazoa above. As regards the structure of 

 protoplasm, the author is a strong adherent of the 

 alveolar theory of Biitschli. The nucleus of Protozoa 

 is described in detail, both as regards constitution and 

 morpholog}-, and special sections are devoted to 

 chromidia, centrosomes, and blepharoplasts ; we miss, 

 however, any discussion of the binuclear hypothesis of 

 the cell, put forward by Hartmann and Prowazek, in 

 relation to the theor}- of the centrosome. The term 

 " blepharoplast " is applied by the author to the 

 kinetonucleus of tr>panosomes, as is usual in Ger- 

 many; we must confess to a feeling of surprise, how- 

 ever, that the author doubts the nuclear nature of this 

 body. 



The section on physiology' is subdivided under the 

 headings " Stoffwechsel" and " Kraftwechsel." The 

 section on reproduction deals w-ith fission, fertilisation, 

 form and development, the Protozoa as unicellular 

 organisms, and theoretical problems of sex and repro- 

 duction. Under the fifth of these headings the author 

 discusses the hypothesis of nuclear dualism (more cor- 

 rectlv dualism of the chromatin-substance) of the 

 protozoan organism put forward by Schaudinn and 

 Goldschmidt; according to this view, ever}- protozoon 

 is be regarded as containing tw-o nuclei (or rather tw-o 

 kinds of chromatin), a " Stoffwechselkern " of vegeta- 

 tive somatochromatin, and a '' Geschlechtskem " of 

 generative idiochromatin. The author considers (and 

 we fully agree) that there are not two distinct kinds 

 of nuclear substance, but that one and the same sub- 

 stance is responsible both for functional activity and 

 for heredity in the protozoan body; he quotes 

 Hertwig's opinion in support of his own, to the effect 

 that somatochromatin is idiochromatin of w-hich the 

 activities are awakened, and idiochromatin is somato- 

 chromatin in w-hich the activit}- is dormant but can 

 be renewed under suitable conditions. He considers, 



B 



