1903] BRIEFER ARTICLES 67 
death and decay of the tubercles most of the contained rhizobia also 
die, but some escape into the soil and serve to infect other roots of the 
same host species. No comparisons were made between summer and 
winter soil to determine the comparative number of rhizobia present. 
It is, however, highly probable that the conditions are much as with 
the rhizobia of summer and winter tubercles. The tubercles of annuals, 
like the bean, pea, Spanish pea, etc., die and decay at the close of the 
vegetative period and many of the contained rhizobia escape into the 
soil. Many are no doubt killed and assimilated by the host plant shortly 
before the close of the vegetative period; according to some authori- 
ties during the seed- and fruit-forming period of the host plant. 
The following are the conclusions based upon the observations 
recorded : 
1. A considerable number of rhizobia of biennial and perennial 
plants forming root tubercles are killed during the winter months. 
2. Root tubercles of perennial herbaceous legumes attain their full 
growth during the early part of the first season. 
3- Most root tubercles of perennial herbaceous legumes die and 
decay at the close of the second season, returning only a part of the 
contained rhizobia to the soil. Many of the rhizobia are assimilated 
by the host plant during the period of fruit development.—ALBERT 
SCHNEIDER, California College of Pharmacy, San Francisco. 
