5&2 Journal of Applied Microscopy. 



considered in detail. Some of the topics are : the washing out of the fixing 

 agent and its significance in theories of staining : staining in simple staining 

 solutions without differentiation : double staining with simple solutions ; simul- 

 taneous double staining with mixed stains: impregnation : objections to the 

 physical theor}- of staining: chromatin, and the fundamental doctrines of stain- 

 ing. Here again experiments upon substances of known chemical composition 

 occupy a large part of the space. 



Part III deals with the structure of protoplasm. Spindles, centrosomes, and 

 radiations are thoroughly discussed, and artificial figures are compared with 

 those occurring normally. Chromatin is treated in the paragraphs on granules. 

 The various theories of the structure of protoplasm, as the granula theor)-, the 

 network theor}-. the filar theor}-. and the foam structure theor}-, are critically 

 reviewed. 



Investigations upon the structure of protoplasm demand not only extreme 

 skill in mechanical manipulation, but. also a knowledge of the principles under- 

 lying fixing, staining, and other details of micro-technique. This book puts the 

 whole subject of micro-technique upon a firmer and more philosophical basis. 

 and gives an up-to-date discussion of modern theories of protoplasmic struc- 

 ture, c. J. c. 



Atkinson, G. F. Studies on Reduction in Plants. In Arisc^ma tr/'p/iyllinn the writer finds 

 Bot.Gaz. 28: 1-26, pi. 1-6, 1899. ^j^^^ ^ qualitative reduction of the 



chromatin takes place during the first mitosis in the pollen mother cells. Arisa7na 

 differs from forms hitherto described, in that both a longitudinal and a trans- 

 verse division of the chromosomes takes place during the first mitosis in the 

 pollen mother cell. Korschelt's work on the annelid Ophryotrocha is quoted as an 

 instance of a reducing division during the first mitosis, and Belajeff's work on 

 Iris is cited as a case of reducing division during the second mitosis in the 

 pollen mother cell. Calkin's work on Fteris and Adiantum is also quoted as an 

 example of a reducing division in plants. 



In Tril/ium grandiflonim there is also a reduction division, but it occurs at 

 the second mitosis in the pollen mother cell. The author suggests that the 

 explanation of the divergent and often contradictor}- accounts of various investi- 

 gators is to be sought in the fact that they have studied dift'erent plants in which 

 the types of mitosis may be ven,- dift'erent, so that in one there may be a mass 

 (quantitative) reduction, in another a numerical (pseudo) reduction, and in 

 another a reducing (qualitative) reduction. c. j. c. 



This book is designed as a practical 

 Hacker, Dr. Valentin. Praxis und Theorie . , • ^t .1 r n .. 



der Zellen und Befruchtungslehre. Jena, g^'de m the Study of cell Structures 

 Gustav Fischer. Pp. VIII-|-26o. 137 text and fertilization both in plants and 

 gures, I 99. mar s. animals. It dift'ers from such books 



as O. Hertwig's Zelle und Gewebe, and E. B. Wilson's The Cell i?i Development 

 and Inheritance, in that it gives practical directions for collecting, preparing, 

 and studying the various forms. As might be expected from a zoologist, the 

 author has made the zoological side very dominant, only five of the forty objects 

 given in the table of contents being botanical. There are sixteen exercises, each 



