22 Brannon. — The Structure and Devetopment of 
in the frail walls of these old exhausted cells, would almost 
certainly have given preparations showing the empty cells 
connected by wide openings, thus leading to the conclusion 
that cell-fusion between these auxiliary cells had taken place. 
During much of the time devoted to the initial study of 
Grinnellia , many attempts were made to carry it through 
paraffine for the purpose of sectioning, but none were success- 
ful. It was found on examination from time to time, as the 
plants were being prepared for imbedding, that they endured 
the action of absolute alcohol and the oils very well ; but in 
every case the tissue was found to be too delicate to endure 
the temperature necessary in the final process of imbedding, 
even when the softest paraffine, melting at the low temperature 
of 45 0 C., was employed. 
After repeated failures with paraffine the celloidin method 
was tried. This proved somewhat more satisfactory, though 
the prolonged treatment of sections with the oils used in 
dissolving celloidin shrivelled and distorted them to such 
an extent as to render observations partial and uncertain in 
their results. Finally, having secured an abundance of 
favourable material, and adopting the freezing methods and 
apparatus perfected by Mr. W. J. V. Osterhout of Brown 
University, the successful study of the cystocarpic develop- 
ment of Grinnellia was undertaken, and very gratifying 
results obtained. 
The great advantages of the freezing method in work on 
Grinnellia are appreciated in the ability to make rapid 
preparation of fresh tissue and to secure a great number 
of sections with comparatively little labour. This latter 
advantage makes the process especially valuable in showing 
the relation of the evanescent trichogyne to the procarp. It 
is difficult to observe this relationship by other methods, 
since many of the cystocarps may be too young or too old 
by a few days to show clearly the early stages of procarpic 
development. 
A brief summary of this method may be given as follows : — 
A portion of the fresh frond is arranged in several layers, 
