February 24, 1911] 



SCIENCE 



305 



matters of molecular concentration, osmotic 

 tension, cryoscopy, periodicity, Ostwald's sur- 

 face energy, relations to thermodynamics, 

 diffusion, fields of force, all considered as ele- 

 mentary factors which enter into the synthesis 

 of organic phenomena. In the matter of dif- 

 fusion Leduc's experiments show curiously 

 close parallels with organic processes, pro- 

 ducing geometrical forms, circulation of 

 " cytoplasm," " life " which survives freezing 

 or drying, pseudosegmentation of a " germ," 

 and phantoms of karyokinetic figures. Espe- 

 cially striking are osmotic growths, which 

 are unquestionably the most complete paral- 

 lels between the lifeless and the organic which 

 have been devised. Following Leduc's for- 

 mulse one may cause " organisms " to grow 

 which are curiously like algse or fungi. 

 Leduc points out that they will grow roots, 

 stems and " fruit," the last sometimes ap- 

 pearing quite different in color. The growths 

 have their periods of " youth, maturity, senil- 

 ity and death," they exhibit periods of activity 

 and rest, they show cell-like divisions, definite 

 form relations, and a circulation of their fluid 

 contents; they will repair wounds, and show 

 responses to external and internal stimuli. 

 Peculiarly sensitive are these colloidal osmotic 

 productions to changes in milieu : thus those 

 "growing" around the sides of a jar will oc- 

 casionally behave differently from those in the 

 middle. Each salt, it appears, has its specific 

 morphogenic properties. With some salts the 

 " productions " are first attached : they then 

 become amoeboid and motile, sometimes form- 

 ing spicules at the surface. The degree of 

 concentration of the solution, also, determines 

 sensitively the branching or the heaviness of 

 the growth, the outcome of reactions which 

 Leduc compares, by numerous chemical 

 formulse, to metabolism. 



Altogether Leduc's book is interesting and 

 it deserves to be carefully read. We need not 

 admit that it is biology; but we must admit 

 that the inorganic conditions which here are 

 given detailed consideration have occurred 

 and are occurring constantly in organisms. 

 And we shall be apt to admit that the syn- 

 thetic method promises results which will 



prove of great value. Leduc would be the first 

 to agree that living substance may not be 

 synthetized for ages, if at all. But each ad- 

 vance brings the goal nearer, in the solution 

 of single problems, and even of their sepa- 

 rate components. Leduc points out the im- 

 mediate task of synthetists, and an essential 

 one, is not the artificial production of 

 albumenoids, but of a chlorophyllian sub- 

 stance which will decompose carbon-dioxide 

 dissolved in water and be capable of assimi- 

 lating carbon. In this direction one recalls 

 the interesting notes of Matthews and of Mc- 

 Pherson in recent numbers of Science. 



Bashford Dean 



Praktikum der Bakteriologie und Protozool- 

 ogie. Von Kisskalt und Hartmann. 

 Zweite, erweiterte Auflage. Zweiter Teil : 

 Protozoologie. Von Dr. M. Haktmann. 

 Pp. vi -j- 106. Mit Y6 teils mehrfarbigen 

 Abbildungen im Text. Jena, Gustav 

 Fischer. 1910. M. 4. 

 The task of securing adequate laboratory 

 material for instruction in protozoology has 

 been considerably simplified by the " Prak- 

 tikum " of Kisskalt and Hartmann. The 

 author of the second part. Dr. Hartmann, is 

 the director of the laboratory of protozoology 

 in the Eoyal Institute for Infectious Diseases 

 at Berlin, a pupil of Professor R. Hertwig 

 and the successor of Schaudinn as editor of the 

 Archiv fiir Protistenhunde. The work is 

 therefore authoritative and reflects the cur- 

 rent practise in one of the greatest centers of 

 research. The hand-book is written primarily 

 for the medical student and includes only 

 parasitic forms and especially those of medical 

 interest. It is not a book therefore primarily 

 for the biological laboratory though the range 

 of forms it discusses is sufiicieutly wide to 

 make the work indispensable to every student 

 of the protozoa, and of greatest value in all 

 laboratories in which the protozoa are studied. 

 The second edition has been considerably 

 enlarged by the addition of a section on the 

 technique of investigation in protozoology and 

 by a chapter on the Myxosporidia and the 

 Sarcosporidia. A number of new parasitic 



