200 Studies in Bacteriosis 



(4) Sterilisation of the pruning knife in cases where the disease has 

 been noticed, especially while pruning the diseased plant and before 

 passing from the divseased plant to healthy ones. This might easily be 

 effected by wiping the blade of the knife with a rag soaked in 2 per cent, 

 lysol or some similar disinfectant. The prunings from diseased plants 

 should not be thrown to the ground but carefully collected and burnt. 



(5) The cutting away of a diseased stem and allowing a lateral to 

 develop will often give a clean plant. 



(6) Care in the use of artificials to see that potash is present in 

 sufiicient quantity and nitrogen not inordinately abundant. 



COMPARISON OF THE STRIPE DISEASE WITH THE GRAND RAPIDS 



TOMATO DISEASE. 



The Grand Rapids Disease has been investigated by Smith (8) and 

 attributed to a bacterium which he has named Aplanobacter michigonense. 

 It has been stated earlier that an organism was isolated from " Striped " 

 plants which seems to agree closely with A. michiganense. The organism 

 is a small oval non-motile rod, gram positive, growing well on neutral 

 or slightly acid media forming a very viscid, deep orange-coloured slime, 

 so viscid in fact that, when the culture is young, difficulty is experienced 

 in lifting any of the slime on a platinum wire. In old cultures this 

 difficulty is not so great. The colour of litmus milk remains unchanged 

 for 10 days to 14 days at 22° C. and a thick deep yellow mucilaginous 

 ring and pellicle form at the surface, the casein is not coagulated but 

 becomes slowly digested ; at the end of a month the whey is quite clear 

 and red, and a precipitate containing tyrosine crystals is found at the 

 bottom of the tube. In untinted milk the yellow ring is again the only 

 noticeable change during the first fortnight, after which the casein is 

 digested slowly without coagulation and the whey becomes quite clear 

 and bright yellow in colour. Nitrates are not reduced, slight turbidity is 

 formed in the nitrate broth but no ring or pellicle is produced, hi three 

 days at 22° C. the broth becomes very mucus-like and the organism is 

 found in short chains appearing almost like a strej)tococcus, except that 

 the component cells are oval in shape. Dunham's solution became 

 slightly turbid and muciis-like, indol was produced. 



No growth was observed in 10 per cent, peptone containing 2 per 

 cent, of glucose, lactose oi- saccharose and the colour of the litmus 

 remained unchanged even after a month in the incubator. No growth 

 was obtained in Uschinsky solution. 



A comparison of these reactions with those dosciibed by Smith for 



