142 Report ofr DEPARTMENT OF BACTERIOLOGY OF THE 
ters. He found that although the crystallizable and diffusibie 
nitrogenous compounds (amids) passed through the bougies, 
some 90% of the soluble protein matter might be held back. 
Although all the bougies used by him retained considerable 
of the nitrogenous matter his trials showed that this passed 
much more fully through a new one than through the same 
after it had been used several times. In later trials (1900) 
he passed milk through these filters and found that the enzym 
galactase was removed thereby. 
These experiments of Freudenreich came to our attention 
after we had completed our filtration experiments. In review- 
ing our records in their light we find that we used new filters 
or those which had been used for similar work only a few 
times. We are assured, therefore, that even the new bougies 
largely reduced the enzym content and that none that we 
employed, some of which had been used several times, wholly 
eliminated it. 
The results of others who have tested the relation of filtra- 
tion to enzym content of cultures of similar soft-rot bacteria 
may profitably be reviewed in this connection. 
Potter (1900. 448) found that filtration through Pasteur- 
Chamberland filter did not remove the enzym produced by his 
Pseudomonas destructans. Laurent (1899) found similar bac- 
terial enzyms to pass through porcelain while Spieckermann 
(1902) found that after passing culture broths through the 
Reichel porcelain filter the sterile broth had not the least en- 
zymic action. Van Hall (1902) found that the juice expressed 
from potato decayed: by the invasion of B. subtilis when passed 
through the porcelain filter retained the property of rapidly 
destroying the potato tissue. He also found (Zeitschr. f. 
Pfky., 1903) similar but weakened action in the juice from 
iris invaded by his Bacillus omnivorus, when this was passed 
through a porcelain filter. In other trials he found filtered 
broths lost all activity. We are at a loss to reconcile some 
of these results with our own and the others except by ap- 
pealing to differences in the filters. 
