INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 591 



have imagined, a secreted product, but that it is a living tissue ; this 

 view, however, is now old, and appears to owe its origin to Professor 

 Owen, who* pointed out the striking similarity which obtains 

 between dentinal and ordinary osseous tissue. 



Ovary of Mammals. t — Dr. Jules Macleod (of the Ghent Histo- 

 logical Laboratory) describes the ovaries of the bat (pipistrelle), 

 mole, and stoat. Successful results were obtained by the method of 

 double coloration. The ovary and oviduct are very closely connected 

 by means of their serous investment, as in other mammals except 

 man. The parenchymatous zone of the stroma is not resolvable into 

 the separate layers (cortical, subcortical, and follicular), distin- 

 guished by His. In the stoat this zone, with its peripheric lobules, 

 is copiously developed and sharply limits the included medullary 

 vascular stroma ; while in the mole and bat these two portions of the 

 stroma lie side by side, the one not being wrapped round the other. 

 In the bat their structure is nearly identical. The ovary of the 

 adult mole offers seasonal diflferences as to size, structure, and orien- 

 tation, which are not constant, and merit further study. The serous 

 endothelium of the bat passes gradually into the adjoining ovarian 

 epithelium. The cuboid epithelium of the mole is very distinct from 

 the endothelium of the serous layer, which, as in the bat, is excep- 

 tionally extended over most of the ovary. In the stoat the epithelium 

 is nearly cyliudric. The adult intertrabecular ovarian stroma of 

 these three mammals is largely made up of elements comparable to 

 the Plasmazellcn of Waldeyer, whose interpretation of the Graafian • 

 follicles also coincides with the description of their structure and 

 development here given. Finally, the ovary contains medullary 

 cords, v/hich the author, following Balfour, regards as homologues of 

 the male seminiferous tubules. These cords are especially abundant 

 in the mole, less so in the bat ; in both the contiguous ovarian surface 

 is closely invested by its capsule, as is the testicle by its albuginea. 



Influence of Saline Solutions on Protoplasm. | — The researches 

 of M. Costerus were stimulated by the results obtained by Professor 

 de Vries in examining the influence of acids on vegetable substances. 

 The solutions employed by the former contained chiefly chloride of 

 sodium or nitrate of potash, and the object of examination was most 

 frcc^ucntly the red beet-root. 



The following was his method of investigation : — In glass 

 capsules, about 3 cm. high, he placed some very thin slices of beet- 

 root, which were covered over by water ; similar slices were immersed 

 in a 10 per cent, solution of sea-salt. It resulted from those experi- 

 ments that, at the end of a few days, the slices in the salt-solution 

 comj)lctely lost their colour, whereas thf)so in pure water for some 

 considerable time after, retained their colour. Similar results were 

 obtained with solutions of nitrate of potassium. 



To what was this efl'oct due ; is more oxygen absorbed by water 



* ' ComptcH RpikIuh,' ix. p. 784. 



t ' Aroli. (Ic liiolo^'io," i. (1880) pp. 241-278 (2 platfs). 



X ' Arch. NeiTl. Sci. o.\nct. ( t iiat.,' xv. (1880) p. 148. 



