1922] KNUDSON—ORCHID SEEDS 17 
On Ashby’s medium plus 1 per cent glucose, the beneficial 
effect of the organism was more apparent. There was a marked 
increase in the width of the embryos. In the inoculated cultures 
all the embryos had produced one or two leaves and the embryos 
were dark green. In the uninoculated cultures only 25 per cent 
of the embryos had produced a leaf point and the embryos were 
chlorotic (fig. 2). On both solution B and Ashby’s+1 per cent 
glucose, the influence of Bacillus radicicola was so strikingly bene- 
ficial that it was observable immediately. 
In the cultures with o.10 per cent glucose or no glucose, the 
influence of B. radicicola seemed to be injurious, for in all the 
inoculated cultures the average width of the embryos was less 
than in the uninoculated cultures. 
The cause of this favorable influence of Bacillus radicicola on 
the growth of orchid embryos remains yet to be determined. Some 
experiments were also made in which the cultures were inoculated 
with Azotobacter sp. In every case, however, there was a marked 
retardation in growth. 
Transplanting experiments 
On July 12, seeds of Laelia-Cattleya hybrid no. 2 were sown on 
solution B plus 2 per cent fructose plus 1.5 per cent agar. As 
culture vessels, Erlenmeyer flasks of 150 cc. capacity were used, 
and 30cc. of the medium was employed. On October 14 the 
embryos were just on the verge of producing the leaf point. They 
were then transferred to six Erlenmeyer flasks (D 18 to D 23) 
containing 50 cc. of nutrient media, as follows: Pfeffer’s solution + 2 
per cent glucose+o.1 cc. carrot decoction. 
On March 1, 1920, the seedlings in cultures D 18 to D 23 had 
two and three leaves with a pronounced protocorm, and from the 
protocorm one and two roots had grown out, the roots varying 
from 1 to 3cm. in length; whereas in the corresponding tube 
cultures, four seedlings in a hundred had produced roots, and these 
roots were only 2 mm. and 3 mm. in length. On March 11, 1921, 
seedlings were transferred from cultures D 22 and D 23 to liter 
Erlenmeyer flasks containing 300 cc. of solution B plus or minus 
Sugar. Eight cultures were made, four with 2.0 per cent sucrose 
