420 Campbell. — Sludies on the 
spore within the sporangium until after the fertilization of the 
archegonia. Miss Lyon also confirms Fitting’s account of 
the real nature of the protoplasmic vesicle of the young 
macrospore. 
Miss Lyon, in her paper, criticizes the work of the writer 
on Kraussiana , and this led to a re-examination of the 
preparations upon which the account was based as well as 
the making of a number of new preparations of the same 
species. The result was to confirm in every detail the state- 
ments previously made, with the single exception of the point 
which had been corrected in Fitting’s paper. Being at a loss 
to see how Miss Lyon could have reached such very different 
results, she was written to on the subject, and it turned out 
that she had misunderstood the writer’s use of the term 
‘ spore-cavity/ which was interpreted as synonymous with 
‘vacuole.’ In reality her results agreed closely with those of 
the writer. It seemed well, however, to make a definite 
statement as to the real facts in the case, especially as the 
new preparations filled several gaps which had been left in the 
older series of preparations. 
Methods. 
The earlier preparations were made from material fixed 
with i °/ o chromic acid, double-stained with alum-cochineal 
and Bismarck-brown. In making the new preparations 
Flemming’s weak solution was used for fixing, and the 
triple safranin-gentian-violet-orange stain was employed. In 
this way, especially in the younger stages, very beautiful 
differentiation of the nuclei was obtained. In the later stages, 
especially after the spore-cavity became completely filled up, 
the strongly staining coarse albuminous granules often made 
it difficult to clearly recognize the nuclei. 
In fixing the spores and embedding them for sectioning 
the individual spores were removed from the sporangia and 
sectioned separately. Owing to the brittle exospore, some 
trouble was experienced in sectioning, but by using hard 
paraffine this was to some extent corrected. 
