84 MIDLAND NATURALIST. 
very slight contact of the coverglass with my finger, revealed the 
fact that the filaments where ‘‘ knee joints’’ were present became 
completely disintegrated to such an extent that all or nearly all of 
the cells in such filaments separated from one another and became 
free floating ones that presumably would be able each to develop by 
repeated division into new filaments. Normally the cells in a 
filament of Mougeotia hold firmly together so that it more readily 
breaks across the middle of a cell that at the place when two cells 
are attached. The process of jaming or disturbing such material 
was subsequently advertently tried and the same disintegation of 
filaments resulted, in material with ‘‘knee joints” present. More- * 
over it was observed that some days after the appearance of the 
bendings the amount of Mougeotia increased enormously, and espe- 
cially the number of filaments was greatly multiplied, thus lending 
favor to the supposition that the disintegration of the cells following 
the phenomenon of ‘‘ knee joints’’ was a device for increasing the 
number of plants, each free floating cell of subsequent division 
becoming a new individual. Looked at in this way the bendings 
might be interpreted as a phenomenon preliminary to the process of 
vegetative multiplication of the individuals, and may be considered . 
as the first step in a process of multiplication of the plants. 
Though no protoplasmic contents can apparently pass from one 
filament to the other at the point where the union of the bends, still 
it is not impossible that certain more or less soluble substances 
exchange at this point by osmotic pressure between the two 
filaments. Such substances might affect by mutual exchange the 
condition of the protoplasm of either individual plant one of the 
results being the tendency of the cells to disintegrate. These 
conclusions or theories may be unwarranted by the premises, but 
certain it is that the ‘‘ knee joints’’ are not stages of conjugation 
as I have found to be a prevalent belief, and likely it is that they 
serve some important function in the plant whatever this be, and 
though they may have been frequently observed either their purpose 
has been misinterpreted or overlooked. "Though the explanation 
here offered is probably both unsatisfactory and, owing to more 
detailed and continued investigation unwarranted, we offer it only 
as a suggestion or an explanation, and feel that we may insist that 
“knee joints’’ have no bearing on the conjugation process whatever, 
as none of the stages of the latter in id way resemble the phe- 
nomenon in question. 
