488 Harper—Nuclear Phenomena in the Smuts. 
formed. In this particular it is similar to the conjugation of 
such infusorians as Paramoecium , where the two conjugating in¬ 
dividuals both maintain their individuality and continue to 
divide after the fusion as before. In Paramoecium , however, a 
complicated system of nuclear changes has taken place, result¬ 
ing in the loss by disintegration of certain daughter nuclei and 
the providing of each Paramoecium with a new micro- and ma¬ 
cronucleus to which both individuals have contributed. The oc¬ 
currence of the fusion after a prolonged period of vegetative 
activity in the yeast budding and the reduced vitality of indi¬ 
viduals which do not succeed in fusing, is another point of re¬ 
semblance between the process here and in the infusorians, 
where Maupas has shown that after a number of ordinary vege¬ 
tative divisions, somewhat definite for each species, the indi¬ 
viduals die unless conjugation takes place. Maupas 1 also finds 
that the conjugation can only occur when starvation threatens, 
just as is the case with the smut conidia. In the case of the 
latter, however, fusion is at the most only necessary to render 
the individuals a little more resistant to a period of reduced 
nutrition, and as long as the food supply is abundant they show 
no diminution of vitality; while the infusorians, in spite of 
abundant food, inevitably die of “ senile degeneration ” unless 
conjugation occurs after a certain number of generations. 
When fresh beerwort is supplied to the cultures containing 
fused pairs they begin budding off conidia as before. (Fig. 22.) 
The process begins frequently by the formation of a rudimen¬ 
tary germ tube as if a mycelium were to be formed. Each spore 
pushes out in a short tube of practically the same diameter as 
itself. Cross walls are then put in, cutting off one or two cells 
from the end of this tube, and these cells then produce conidia 
by budding. This budding is well figured by Brefeld. 2 In 
making fixed and stained preparations the conidia are generally 
broken off, leaving the spore pairs with the germ tubes alone. 
Sometimes only one of the two spores germinates (Fig. 21), 
though as a rule both do. When only one germinates the nucleus 
1 E. Maupas, “Le rejeunissement karyogamique chez les cilies.” Arch . 
de Zool. Exper. et g&ndr. 2e. Ser., Vol. VII. 
2 Loc. cit., Tafel. 
