Apbil 16, 1909] 



SCIENCE 



617 



been effected, chiefly, by cutting out about 30 

 pages on special organology, and 60 pages on 

 " Arcbitektonik " or morpbology; also by 

 omitting many figures and parts of tbe de- 

 scriptive matter, as well as changing other 

 parts. Some new paragraphs, mostly of a 

 historical nature, have been inserted. 



The second part of the book or " special 

 part" deals with the descriptive histology of 

 some 40 animal types taken in almost syste- 

 matic order. The entire histology of each 

 form is seldom discussed, but only such por- 

 , tions as are characteristic, or as fill out gaps 

 in the rather rough and incomplete system of 

 tissue classification, are described in the au- 

 thor's thorough and scholarly way. The 

 whole part is divided, very arbitrarily, into 50 

 lessons as a convenience to teaching. 



This special part is, of course, the largest 

 and most substantial part of the book. To 

 estimate very crudely the amount by which it 

 has been reduced from the corresponding part 

 in the old edition, it may be said that in the 

 latter it occupied 685 pages, while in the new 

 form it is contained in 445 pages. This re- 

 duction has been secured by taking out de- 

 scriptions of a few entire forms and of certain 

 of the tissues of other forms. Care has been 

 shown in doing this, as a rule, to remove those 

 parts which in any sense duplicated or paral- 

 leled other parts. 



Comparatively little has been added to this 

 part of the book, although it has been carefully 

 worked over and much changed in many de- 

 tails. One improvement consists of the addi- 

 tion in several places of appropriate details of 

 histogenesis. The omission' of any allusion to 

 the comparatively rare but important tissues 

 that produce light and electricity is a disap- 

 pointment to the reviewer; the more so that 

 other rare tissues of possibly less fundamental 

 importance have been left in, as a quite ex- 

 tensive account of the structure and develop- 

 ment of the nettle cells of Physophora, All 

 reference to gas secretion has been omitted, 

 although it was treated of in the first edition 

 and is a matter of scientific importance. 



The index is short, too short even when one 

 considers that the method of arrangement and 

 table of contents both supply much that is 



omitted in its numbers. As an instance, a 

 student or research man would have to search 

 through nine pages of text to find the concise 

 but valuable account of muscle structure in 

 Peripaiiis (pp. 131-132), there being no indi- 

 cation of this item, in index or table of con- 

 tents. Were he to start on a comparative 

 study of muscle he would have to search care- 

 fully in other places as well. This also holds 

 true for other tissues. 



Personally the writer woidd have preferred 

 to see an enlarged edition of the former 

 " Lehrbuch," strengthened by certain addi- 

 tions and revisions. One can not help feeling 

 that the new edition is, in part, a sacrifice of' 

 scientific ideals to practical or even commer- 

 cial demands. An advanced student should 

 really have the old edition as well as the new,, 

 even if he should not prefer the fijst edition 

 outright. It is to be hoped that the author- 

 will, in the near future, give to advanced stu- 

 dents of scientific histology a third and fuller 

 edition. 



The printing, figures and general make-up 

 are all that can be desired, and the very few 

 errors of typography and lettering are a negli- 

 gible quantity; the bibliography is fuU and 

 complete. The book should be in the hands 

 of every advanced student of histology as well 

 as of other zoological subjects. 



Ulrio Dahlgren 



Prohleme der Protisienkunde. I. Die Try- 

 panosomen ihre Bedeutung fiir Zoologie, 

 Medizin und Kolonialwirtschaft. Von F. 

 DoPLEiN, Ao. Professor der Zoologie an der 

 TJniversitat Miinchen. Jena, Gustav 

 Fischer. 1909. Pp. 1-57. 

 Under the above title there has appeared an 

 excellent article on the present knowledge con- 

 cerning trypanosomes. 



The trypanosomes are small one-celled ani- 

 mals bearing a fiagellum on one end and an 

 undulating membrane on the side of the body. 

 They are classed under the protozoan group 

 Flagellata. They are parasitic in the blood of 

 vertebrates and cause in mammals serious 

 diseases, such as " nagana," " surra," " dour- 

 ine " in horses and " sleeping sickness " in 

 man. The pathogenic forms are distributed 



