SUMMARY. 15 



methodo Gram non colorantur. Nitnim non redicritur. Lac sterile 

 alcalinum fit; initio translucidiim, flaviim ))ulli(luin dcmum opaciim, 

 brunnou et gelatiim; casein non segregatur. Inter tcmperaturam 

 29° C. et temperaturam —5° C. culturae crescimt. wSi culturae novae 

 in infusione carnis { lioram in temperatura 46° C. tenentur, moriuntur. 

 Inter temperaturas —5° C. et — 15° C. per decern dies non moriuntur. 

 Si baculi siccantur vel soli exponuntur, celeriter moriuntur. In foliis 

 vivis Brassicae oleraceae aspergendo inoculatis, maculae in 3-4 diebus 

 producuntur. Contagium in stomatibus fit. 



SUMMARY. 



The leaf-spot disease of cauliflower described in the preceding pages 

 is due to a bacterial organism, which was secured in pure culture from 

 the leaf spots and inoculated into healthy cauliflower plants, with 

 production of the disease. Healthy cabbages inoculated with the 

 organism also showed similar infection. 



Inoculations during July, 1909, were unsuccessful because of the 

 higher temperature. 



The heads of cauliflower gave no satisfactory results when inocu- 

 lated with the organism. 



The name Bacterium maculicolum has been suggested for this organ- 

 ism. It is a schizomycete, pathogenic to crucifers, causing numerous 

 small spots on cauliflower and cabbage. Entrance by way of the 

 stomata. Organism white, but causing a greenish fluorescence in 

 some media (beef bouillon +15, beef gelatin +10, beef agar +15, 

 Uschinsky and Fermi). Motile by means of one to several polar 

 flagella. A short rod (1.5 to 3 // by 0.9 /i), single or in chains in 

 some media (10 to 30 // long on agar; 10 to 24 /x long in beef bouillon 

 plus 4 per cent sodium chlorid). Does not stain by Gram; stains 

 deeply with amyl Gram. 



No spores. Involution forms (found in alkaline beef bouillon) and 

 pseudozoogloese. Aerobic. Liquefies gelatin slowly. Does not 

 liquefy Loeffler's blood serum. Not gas forming. Feeble produc- 

 tion of ammonia, indol, and hydrogen sulphid. Nitrates not 

 reduced. Tolerates acids, citric and malic to + 36 and oxahc to + 34 

 (Fuller's scale). Tolerates sodium hj^droxid in beef bouillon to —25 

 (Fuller's scale). 



Optimum temperature 24° to 25° C. Thermal death point 46° C. 

 Win not grow in beef bouillon ( + 15) or on agar ( + 15) at 29° C. 

 Grows at 0° C. and below. Grows well in bouillon over chloroform. 

 Grows in Cohn's solution. Blues litmus milk. 



The most striking facts about the organism are its ability to grow at 

 temperatures below freezing and its failure to grow at a common sum- 

 mer temperature (85° F.). 



The leaves of the attacked plants fall off. 



225 



o 



