1210 Wisconsin Academy of Sciences, Arts, and Letters . 
tube being much larger than the cells it connects. In these it is 
usual to find all the greater bulk of the cytoplasm with the two 
nuclei has flowed out into this tube. The two cells are left com¬ 
paratively empty while the tube contains a dense cytoplasm and 
has the two nuclei either separate or apparently fusing. 
I have not been able to determine what would become of these 
cells if they could be started growing again. This was found 
impossible as by the time the two nuclei were in one cell the 
cultures were in such a condition from contamination with bac¬ 
teria that it was impossible to give the smut cells a new start by 
adding fresh beer-wort. It would be interesting also to deter¬ 
mine whether these large fusion tubes could cause infection or 
whether even the fused promycelial cells themselves could do so. 
It has generally been assumed that the promycelial cells are the 
equivalents of the conidia but it has not been shown directly 
that they can produce infection. 
Doassansia Alismatis (Hees.) Cornu. 
Infected spots on the leaves of Alisma plantago were fixed in 
Flemming’s Weaker Solution, then imbedded, sectioned, and 
stained either with iron-haematoxylin or the triple stain. 
In the main my work on this species confirms that of Dan- 
geard (12) but I have been able to observe a number of further 
facts on this highly specialized smut. 
A single section will usually show a number of stages in the 
development of the spore-balls; the older ones being in the mid¬ 
dle and the younger ones on the edges of the infected area. The 
spore-balls originate apparently as described by Dangeard as a 
tangle of hyphae in an intercellular space (Fig. 47). From 
these hyphae are budded off the spores as short branches. At 
first the mass of spores is undifferentiated, all containing two 
nuclei, but as thev become more and more tightly pressed to¬ 
gether, the outside ones lose their nuclei and become thick 
walled, forming the outer sterile layer of the spore-ball. Later, 
the two nuclei in each fertile spore fuse. 
The mycelium is difficult to follow but in the spaces formed 
between the spore-balls the hyphae frequently travel straight for 
