[Vor. 3 
424 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
some of the experiments (series 1A-4A, table r) his solution as 
regards concentration of mineral nutrients. It is as follows: 
КН.РО, 4 gram 
MgSO š ESL 
CaCl à - See This is designated solution A. 
H30 100 се. 
To this has been added (NH4)2804 or asparagin as a source 
of nitrogen, and dextrose or saecharose as a source of carbon. 
In most of the work, however (series 5B-15B, 17B-22B, 
table т), it has seemed well to use a modification of the formula 
known as Richards”? solution, used especially by Miss Latham 
in securing the extraordinary results to be referred to later. 
The modification consists merely in varying the sources and 
amounts of nitrogen and carbon furnished, these last being 
the same as employed with ‘‘solution A’’ above. 
The Richards’ solution consisted of: 
КН.РО. 5 gram 
Men, 25 gram Ki I | 
FeCl; E This is designated solution B. 
H30 100 ee. 
Stock solutions of each constituent were made up of appro- 
priate strength, usually such that an equal quantity of each 
was required for any culture. 
For Glomerella Gossypii a modification of the Uschinsky 
solution, as indieated in table r, was employed, since this had 
been found satisfaetory for this organism through other 
workers in the laboratory. For the various strains of Azoto- 
bacter a soil-compost extract containing mannite was em- 
ployed. Three hundred gm. of potting soil and 100 gm. of well- 
fermented compost were each extraeted for 2 hours with 1 
liter of water, then filtered, and the filtrates combined. To 
the mixed extract was added for each 100 ee, the following con- 
stituents: K»HPO, .05 gm., CaCO; 1 gm., and mannite 5.0 gm. 
Kjeldahl flasks of 500 cc. capacity were used as culture ves- 
sels in all cases, and into each were placed 50 ce. of the solution 
required.! The idea of using the Kjeldahl flasks for the cul- 
1 In the bacterial cultures 100 cc. of solution were employed. 
