38 Studies in Bacteriosls 



Uschinshfs solution. No acid and no gas; strong ring and no pellicle. 



Litmus milk. Acid after 24 hours at 22° C, loose curd after 2 days, 

 and whey separated after 4 days, whey clear and colourless ; curd settled 

 to half the volume of the liquid after 7 days, and still occupied one-third 

 of the volume after 2 months. 



Nomenclature. 



The organism is a pseudomonas and does not .agree with any pre- 

 viously described organism. It is therefore believed to be a new species 

 and the name Pseudomonas Proteamaculans is suggested for it. According 

 to the system of the American Society of Bacteriologists it -is represented 

 by the number 221.1313023. 



Control Measures. 



In the present state of our knowledge the control of bacterial diseases 

 is very difficult. In this instance the bacteria gain entrance to the leaf 

 by way of the stomata and are undoubtedly introduced as a result of 

 syringing the plants. The presence of some antiseptic in the water used 

 for syringing which shall be toxic to the organisms and harmless to the 

 plant therefore suggests itself as a possible means of preventing infection. 

 With this end in view the following experiments were made. Test tubes 

 containing 10 c.c. of the solutions given below were sterilised and 

 inoculated with a loopful from an active culture of Pseudomonas Protea- 

 maculans, and after the time stated in each case a loopful was transferred 

 to bouillon agar and plated out. The number of colonies developed at 

 20° C. was determined after three days incubation. 



From this it appears that a solution of mercuric chloride (1 : 10,000) 

 is most effu'ipiil. but, in view of the poisonous natuic of this substance, 



