Decembeb 9, 1910] 



SCIENCE 



837 



would be even clearer, perhaps, to speak of 

 these salts as mono-, di- and tri- potassium 

 phosphates. In all cases it is desirable to give 

 the formula as well as the name of the salt. 



E. E. B. McKenney 

 Laboeatoey of Plant Pathology, 

 BuBEAU OF Plant Industey, 

 Washington, D. C. 



the loan of lantern slides to illustrate 

 lectures on hookworm disease 

 Requests for the loan of lantern slides to 

 illustrate the anatomy and life history of the 

 hookworm and the methods of preventing 

 hookworm diseases have increased to such an 

 extent that I have ordered several extra sets 

 of forty-five slides each. 



These slides will be loaned to medical so- 

 cieties, colleges, schools, teachers' associations, 

 women's clubs, etc., that may desire to use 

 them. The two conditions attached to the 

 loan are: (1) that all requests be forwarded 

 through the secretary of the state board of 

 health; (2) that the slides be returned, ex- 

 press prepaid, immediately following their 

 use. 



Preference will be shown to societies and 

 institutions in hookworm-infected states. 



C. W. Stiles 

 Hygienic Laboeatoey, 

 U. S. Public Health and 

 Maeine-Hospital Seevice, 

 Washington, D. C. 



SCIENTIFIC BOOKS 

 Die Variabilitdt niederer Organismen. Eine 



deszendenztheoretische Studie von Hans 



Pringsheim. Berlin, Julius Springer. Pp. 



216. 



Dr. Pringsheim has done a unique and val- 

 uable piece of work in thus resuming our 

 knowledge of unicellular organisms from the 

 standpoint of the student of variation, hered- 

 ity and evolution. The book is based mainly 

 on bacteriological work, together with work on 

 yeasts and pathogenic protozoa. This is prob- 

 ably just, since it is chiefly in these groups 

 that investigation has gone deep enough to 

 furnish data on the problems of genetics. 



Other groups of protista are not left out 

 of consideration, and a number of the more 

 important pieces of work on these are dealt 

 with, but the pertinent literature is by no 

 means so fully considered as in the case of 

 the groups mentioned. The author is him- 

 self an investigator in bacteriological lines, 

 and has gone over the literature in this and 

 related fields with a fine-toothed comb, bring- 

 ing forth whatever bears on the problems of 

 genetics. This material is well digested arid is 

 arranged in unified sections following a well- 

 laid-out plan. The references to literature are 

 so extensive as to make this a handbook of the 

 subject. 



There is an introduction dealing with varia- 

 tion and inheritance in a general way. This 

 is followed by sections on the struggle for ex- 

 istence in lower organisms (with many con- 

 crete examples, of great interest) ; on the 

 normal " breadth of variability " ; on variation 

 in form and structure; in colonial growth; in 

 movements and reactions; in spore-formation; 

 in production of ferments and of colors; in 

 virulence; variation as evidenced in acclima- 

 tization to heat and cold; to light; to varia- 

 tions in food and oxygen, to poisons, etc. A 

 final chapter gives some general results, with 

 suggestions for future work. 



A broad view is taken of all these phenom- 

 ena, so that the author gives us what might 

 be called a general (though condensed and 

 concrete) treatise on the physiology of pro- 

 tista, dealt with from the standpoint of 

 genetics. From the purely physiological point 

 of view the result serves as a valuable cor- 

 rective for the impressions obtained from 

 physiological works that deal chiefly or only 

 with the supposedly typical. 



The author is very conservative as to the 

 conclusions to be drawn regarding funda- 

 mental problems, though this does not con- 

 ceal the enthusiasm which he feels for his 

 subject, particularly for its future. He holds 

 that it has been proved that in certain cases 

 fluctuating variations have shown themselves 

 heritable, giving rise to new races; and that 

 in some cases direct adaptations have proved 

 heritable — concrete cases being cited for each. 



