2244 Journal of Applied Microscopy 



with HCl (about 1 per cent.). The solution is quite clear, and gi\es good 

 results after any method of fixation. The immersion time is from one-half to 

 several hours. The after treatment is simple, and consists of changes of alcohol 

 from 7<) per cent, up to absolute. The author states that the solution is an 

 effective nuclear stain, that by its use aqueous media can be avoided, and that it 

 does not color celloidin. 



Boveri, Th. Das Problem der Befruchtung. Boveri in this lecture tersely reviews 



Jena. 48 pp., 8 vo, 1902. Review in Jour, the Status of the processes of fertiliza- 

 Royal Micr. Soc, Part 4, 410-419, 1902. 



tion, with a critical discussion of the 



meaning of the various steps. The most important part is, perhaps, his modifi- 

 cation of the view that the chief function of the spermatozoon is to import a 

 centrosome into the inert ovum. Morgan and others showed that alterations in 

 the saline composition of the sea-water resulted in the appearance of bodies like 

 centrospheres in the ova of sea urchin, etc. Loeb showed that in similar con- 

 ditions artificial parthenogenesis resulted. Wilson noticed that in Loeb's 

 experiments bodies like centrospheres appeared in the unfertilized ova, and 

 seemed to initiate the segmentation ; Boveri now suggests " that it is not a 

 centrosome as an organized structure that is introduced into the egg, and there 

 starts the segmentation process, but rather a chemical substance, which in com- 

 bination with the ovian cytoplasm, produces the body in question." Such a view 

 would reconcile much that has hitherto been difficult of explanation in connection 

 with the diverse behavior of centrosomes in different organisms, and even in 

 different cells and tissues of the same individual. 



Michaelis, L., u. Wolff, A. Ueber Granula in The Stains used hitherto only differen- 

 Lymphocyten. Virchow's Arch, 167 : 151- tiate the cell-body of the lymphocyte. 

 160, I tf., 1902. ^ . 



The lymphocyte protoplasm is baso- 



phile. Pappenheim's methyl-green-pyronin mixture differentiates the nucleus 

 and protoplasm. Romanowski's methylen-blue-eosin goes further. For this 

 method two stains are necessary: (1) A methylen-blue solution containing 1 

 per cent, methylen-azure, made as follows : 200 c.c. of a 1 per cent, solution of 

 methylen-blue is boiled with 10 c.c. of ^ per cent, sodium hydroxide for a quarter 

 of an hour, and when cool is neutralized with 10 c.c. of ^ per cent, test 

 sulphuric acid. (This solution is to be obtained from Griibler, in Leipzig, and 

 Leitz, in Berlin, under the name of "azure-blue.") (2) An aqueous eosin 

 solution 1:1000. Immediately before use mix 2 c.c. of the azure-blue solution 

 with 10 c.c. eosin solution, pouring the mixture back and forth several times to 

 ensure complete stirring. It is used for staining regardless of the precipitate 

 formed. To avoid getting this precipitate on the cover-glass the mount is 

 stained in a glass with a concave bottom and placed, face downward, for fifteen 

 minutes, then the preparation is washed off in a very strong stream of water and 

 dried. Those mounts were most satisfactory which had been fixed for an hour 

 in absolute alcohol. Reuter has lately used the precipitate arising from the 

 methylen-blue-eosin mixture as a stain. Each expanded lymphocyte shows, with 

 this stain, a delicate sky-blue protoplasmic cell-body surrounding the violet-red 

 nucleus. In this cytoplasm are seen violet granules as yet undemonstrated by 

 any other method. a. m. c. 



