1540 Journal of Applied Microscopy 



be finished by many various methods. 6. The possibility of embedding by anilin 

 oil without higher grades of alcohol than 70-80 per cent. 7. The short time 

 needed in each embedding solution. a. m. c. 



Eisen, G. The Spermatogenesis of Batrach- Earlier investigations were made on 



oseps. Jour. Morph. Vol. 17, 1900. ^ • 1 1 j j • -1-1 • > 1 



•^ material hardened m Flemming s and 



Hermann's fluids ; later Heidenhain's sublimate-acetic mixture with and without 

 formol was tested. Others also, as Hermann's and Flemming's fluids mixed with 

 sublimate or palladium chloride, vanadium chloride, uranium chloride and osmium 

 chloride. Except the latter the author discarded them all. He believes to have 

 proved that every mixture containing platinum chloride or osmic acid completely 

 destroyed the outer cells. As the testis of Batrachoseps is very small and pos- 

 sesses but few cell layers, all such fixatives must be rejected. Platinum chlor- 

 ide is more injurious than osmic acid, since it destroys the chromatin, while the 

 latter injures the fine structure of the cytoplasm. Osmium chloride is a very val- 

 uable fixative, especially in 1/2 to 1/10 per cent, solutions, although it also pos- 

 sesses the property of blackening the tissues to a less degree than osmic acid. 

 Three to twelve hours are necessary for proper fixation, no shrinking and no 

 blackening occurs, and the outer layers of cells are in good condition as well as 

 the inner ones. An hour's washing in water follows the treatment with alcohol 

 and bergamot oil and xylol, again into bergamot oil and embedded in paraffin. 

 Sections 4 to 6 // thick are cut that every cell may be sectioned. This the author 

 holds to be an essential for good staining. 



Benda's iron haematoxylin combined with congo-red was largely used. The 

 sections left for 24 hours in the following solution : ferric sulphate according to 

 the German pharmacopeia diluted with six times its volume of water, then in 

 concentrated haematoxylin solution containing 10 per cent, alcohol for 48 to 72 

 hours. The best results came from the longer action of the stain. The 

 differentiation is effected by 10 per cent, acetic acid containing a very 

 small quantity of liquor ferri, in 10 to 20 minutes, washed as rapidly as pos- 

 sible, cleared in bergamot oil and mounted in xylol balsam. A triple stain with 

 congo-red, thionin and ruthenium red can be used also. The sections remain a 

 few seconds in a weak aqueous solution of congo-red, then about 10 minutes in 

 thionin in water, and finally differentiated by a very weak aqueous solution of 

 ruthenium red. a. m. c. 



Ra'dl, Em. Arthropod Vision. Zeitschr. wiss. The author considers that not enough 

 Zool. 67: 557-598, I pi-, 1900 (review in importance has been laid on the study 



Journ. Roy. Micr. Soc. pt. i, pi. ^6, igoi). r ^l i. c 4.1, 



■' •' K . F J ' ^ / q£ l-]^g nerve centers of the eye as 



well as of its dioptric apparatus. He believes the key to the problem of 

 arthropod vision to lie in the central rather than peripheral organs. He has 

 exhaustively studied the eye and optic tract in Squilla mantis. After a brief de- 

 scription of the external appearances of the eye, the phenomenon of " double 

 eyes " in arthropods is fully considered. The eye itself is described briefly. 

 Each ommatidium gives off seven nerve fibrils, which unite in a bundle ; as 

 these pass across the space between the basal membrane of the eye and the first 

 ganglion, those from neighboring ommatidia unite to form larger bundles. In 



