' MISSOURI BOTANICAL GARDEN BULLETIN 53 
The organism is a short rod multiplying by fission and 
motile by means of polar flagella. It can be grown in many 
sorts of culture media, forming small, round, white colonies, 
but does not live very long upon agar. The bacterium dif- 
fers from others in not forming open cavities in plants but 
pooayysng vm cells, thus causing proliferation. The galls 
begin to be visible in some cases as early as the fourth day 
after inoculation, growing rapidly in soft young tissues and 
quite slowly upon woody plants. Ready cross inoculation 
and isolation from plants greatly different in structure indi- 
cate that the same organism is probably responsible for the 
injury. The galls are often invaded by saprophytic bacteria, 
nematodes, and various fungous parasites. Their size de- 
pends upon the state of nutrition of the plant, those overfed 
being subject to more rapid growth. The long-continued 
growth which often occurs upon woody tissues is made pos- 
sible by a nearly even balance between the stimulus of the 
parasite and the response of the host. The presence of the 
organism in cells stimulates abnormal growth, resulting in 
the observed tumors. Up to the present no remedies have 
been devised, for although the organism is tible to 
germicides, it is impossible to reach it through the outer 
covering of the gall. Complete removal and burning of af- 
fected parts may reduce the prevalence of disease. 
The belief has recently been expressed by E. F. Smith that 
there is a great similarity between the crown gall of plants 
and malignant cancer of human beings. He claims that 
since, fundamentally, plants and animals are alike, certain 
physical and chemical laws apply equally to both, and since 
plant cancer is caused by a parasite, the same is ig imes! 
true of animal cancer. The cancer of plants has been foun 
to be caused by a single organism, hence he considers that 
a single parasite should be looked for in human cancer. Dr. 
Smith bases his conclusion upon the following resemblances 
which occur in the course of both diseases: (1) no parasite 
being visible; (2) the tumor tissues showing rapid multipli-- 
cation and embryonic character; (3 loss of polarity of these 
tissues; (4) rapid surface growth of tumor, tR presence of 
degenerative changes in proliferating cells; (6) destruction 
of surrounding tissues; (7) invasion of open wounds by 
secondary parasites and saprophytes; (8) frequent return | 
after excision; and (9) presence of atrophy. 
TEST GARDEN 
Many new, interesting, and showy varieties of plants are 
being constantly added to the list of those which may be 
