478 Harper—Nuclear Phenomena in the Smuts. 
that these spores differ in no essential particular from other 
conidia produced by abstriction, and I; shall use this latter 
term. 
While working with Prof. Brefeld at Munster in the summer 
of 1896, I began some studies on methods of fixing and staining 
the nuclei of the smuts. Prof. Brefeld’s experience in grow¬ 
ing these organisms in culture media was of the greatest value 
to me in enabling me to obtain abundant material in all stages 
of development. Aside from the work of Dangeard the nuclear 
phenomena in the smuts have been very little studied and fur¬ 
ther contributions along this line are certainly very much 
needed. 
I have used especially as types material of U. antherarum 
(Pries), U. scabiosa , Sow. U. maydis (D. C.), and U. carbo 
(Tul.). Material of the first was obtained from Lychnis alba y 
the commoner form on Saponaria being found less favorable 
for the study of the conidial fusions, since its conidia do not 
unite so readily as do those coming from the other host. The 
earlier stages of the spore formation were studied however in 
sections of the Saponaria anthers. It is easy to determine 
that Dangeard is right in claiming the presence regularly of 
two nuclei in the young spores. 
In considerably older spores but a single nucleus is to be 
found, and the ripe spores just prior to germination are also uni- 
nucleated. Whether this spore nucleus is really formed by fu¬ 
sion of the two nuclei present in the young spore is a difficult 
question. 
Material fixed in Flemming’s chrom-osmium-acetic solution, 
weaker formula, and stained with the triple stain, shows the 
nuclei as very minute deeply stained bodies. At this stage 
it is difficult to make out nuclear structures; but later in the 
promycelia it is easy to recognize in successful preparations 
a red stained nucleole and blue chromatin net. Dangeard’s 
description of these nuclei as consisting of a nucleole with a 
surrounding hyaloplasm more or less charged with chromatin 
and the whole enclosed in a vesicle with double contour should 
not be taken as indicating any essential difference between the 
structure of these nuclei and those of the higher plants, since 
