882 
weeks I was no longer able to detect any. Ina few tubes there’ 
was no development of bacteria.‘ In these I could study the 
plasomen unobstructed. There was no visible growth, but ex- 
amination showed the unmistakable presence of the plasomen. 
After a time more mature plasomen (dermatosomen) were no- 
ticeable, and these mature plasomen were evidently present 
in greater numbers than when the inoculation was made. In 
about three weeks from the time of inoculation the plasomen 
were nearly all mature, often united into small zoogloz. I do 
not intend to state that all the plasomen, visible and invisible, in- 
troduced with the inoculating needle developed to maturity, since 
it is impossible even to conjecture the number introduced. I was 
at first inclined to ignore them, thinking they were probably by- 
products of the bacteria and cocci. But their presence in inocu- 
lated tubes containing no bacteria, and their behavior with 
sublimate solution indicated that they were true Plasomen. 
I also made plasom cultures from developing tubers of So/a- 
num tuberosum and growing roots of Zea Mays with similar 
results. In all cases there was for a time an apparent increase ih 
the number of mature plasomen coinciding with a decrease in 
number of the smaller plasomen; later only mature plasomen 
were present, and finally these decreased in number until all had 
disappeared. In the case where entire cells were inoculated it 
was plainly noticeable that the mature plasomen increased some- 
what in number until finally the cell contained only those devel- 
oped to maturity. This phenomenon is also often noticeable in 
bacterial cells and cells of hyphal fungi found in culture media. 
The probably correct explanation of these phenomena is as fol- 
lows: The plasomen of Wiesner have a veritable existence and 
are capable of developing into mature dermatosomen outside of 
the living cell. The plasomen can, however, not divide outside 
of the living cell. The reason for this latter supposition is that 
the dermatosomen do not continue to exist. The apparent re- 
production or increase in number is due to the growth of the in- 
visible plasomen to visible dermatosomen. As soon as all plaso- 
men capable of growth have reached maturity apparent reproduc- 
tion ceases, and the dermatosomen begin to decrease in number 
as they are scattered through the culture medium or become dis- 
_ organized. 3 os, 
