Observations on the Development of Some 
Embryo-sacs. 
(WITH PLATE XI.) 
By R. E. B. McKenney, B. S. 
HE study of the development of the embryo-sac was 
T suggested to me in the fall of 1897 by Professor J. M. 
Macfarlane, and has been continued, with interruptions, 
until the present time. I wish to here acknowledge my in- 
debtedness to him for suggestions and criticisms of my work. 
Plants of Scilla hyacinthoides var cerulea, S. campanulata, Lilium 
tigrinum and L. candidum furnished the material for study. 
METHODs. 
As fixatives, I have employed Kleinenberg’s Picro-sulphuric, 
Picro-acetic, Absolute alcohol, and Flemming’s strong Chro- 
mosmo-acetic. The Picric solutions gave very good results. 
Objects not larger than a pea, and with unindurated tissue, 
will be fixed inan hour. The Picric solutions are best washed 
out with 50 per cent alcohol. As a clearing fluid I found 
cedar oil rather better than xylol, since it is less volatile, and 
seems less likely to cause shrinkage. Care must be taken, 
however, to have a// the cedar oil replaced by pure paraffin, or 
good sections will not be obtained. The sections were cut 
on the Minot microtome with a feed of from 6 to Io » and 
fixed to the slide with Mayer’s albumen. As staining agents 
I have used Delafield’s Haematoxylin, Eosin, Guignard’s 
Methylgreen-Fuchsin, Heidenhain’s Iron Hematoxylin and 
Flemming’s triple stain. A combination of Delafield’s Hama- 
toxylin and Eosin proved especially good. 
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