rgt1] DACHNOWSKI—CRANBERRY ISLAND ite) 
caused less retardation on the growth and transpiration of wheat 
plants when inoculated into sterilized bog water than bacteria 
of slow growth. In some cases the isolated pure cultures made 
little headway on beef broth or peat agar media after a period of 
3-5 months, but gave strong inhibition in the growth of wheat 
plants within 3 weeks after inoculation into sterilized bog water 
from their respective plant zones. It is reasonable to assume, 
therefore, that the lack of uniformity in results implies both 
obligative symbiosis and the need of a physiologically balanced 
culture medium. The fact that the organisms are obligate sapro- 
phytes, capable of growing only on substrata similar in composi- 
tion to the character of the surface vegetation, is indicative of a 
close interdependence; their rapid growth in a medium in which 
cellulose and lignin compounds predominate suggests a specific 
cytohydrolytic action. Certain microorganisms in station III 
have been found to possess the ability to dissolve filter paper, 
but their isolation has not been successful. 
It is needless here to repeat the physiological tests which were 
made with a number of isolated pure cultures inoculated in ster- 
ilized bog water. Transpiration figures of wheat plants growing 
in these solutions and various other data have been published 
in an earlier paper (/.c. 9) to show the active participation of the 
organisms in the formation of bog toxins, and their ability to inhibit 
during the processes of denitrification and dehydration the growth 
of plants alien to the habitat. With these suggestions in mind, 
the results on the bacterial reactions in culture media submitted 
above may now be summarized as follows: 
Peat soils are very rich in bacteria inducing diastatic, inverting, 
proteolytic, cytohydrolytic, and reducing action. 
The organisms vary in kind and number with the nature of the 
substratum. 
The majority of the forms are found to thrive as saprophytes, 
digesting the débris in the upper layer of the peat substratum and 
aiding in a partial disintegration of the accumulating deposit. 
Many forms thriving as saprophytes among the indigenous flora 
give little aid in the elaboration of food eran to invading or 
introduced plants. 
