DEVELOPMENT OF THE OVIDUCT IN THE FROG. 273 
The Development of the Oviduct in the Frog. 
By 
Ernest W. MacBride, B.A.(Cantab.), B.Sc.(Lond.), 
Scholar of St. John’s College, and Scholar of the University of London. 
With Plates XII and XIII. 
THE investigation which forms the subject of the present 
memoir was commenced in July, 1890, at Mr. Sedgwick’s 
suggestion. A collection of tadpoles, which were preserved in 
the Morphological Laboratory, Cambridge, was first examined 
without result. None of them showed any trace of the ovi- 
duct, though in some cases both pairs of limbs were well 
developed. Through the kindness of Mr. Sedgwick I was 
enabled to procure a considerable number of Frogs, in which 
the tail was being absorbed or had just vanished ; and amongst 
these I found all the necessary stages for my work. 
The material was treated in some cases with corrosive sub- 
limate, and in other cases with Perenyi’s fluid, and preserved in 
alcohol. Both methods seemed to yield equally good results. 
The stain employed was borax carmine; twenty-four hours 
in this I found to be quite sufficient, a longer period produced 
too deep a coloration. It was found in all cases necessary to 
decalcify the specimens; this was effected by HNO, of 
strengths varying from 1 to 10 per cent. Strange to say no 
difference in the result was observable, whatever the strength 
employed. I should recommend about 3 per cent. for twenty- 
four hours. 
Material preserved in picric acid proved to be utterly un- 
suitable. 
