INTUMESCENCE8. 



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in oxidizing enzymes than were the healthy cells. What 

 possible effect the production of such oxidizing enzymes 

 will have, will for t the present have to remain unde- 

 termined. Sorauer 31 explains that the intumescences 

 formed as a result of spraying with Bordeaux mixture on 

 potatoes, were due to a tendency on the part of the plant 

 to equalize the water present within the cells as a result of 

 the death of the overlying epidermal cells ; but this can 

 hardly hold in the case of the cauliflower intumescences 

 because these formed within the leaf tissue before there 



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were any signs of death on the part of the epidermal cells. 

 Whatever the actual relationship between the sprayed 

 salts and the protoplast may be, one is obviously dealing 

 with a condition of chemical stimulation of living cells 

 hitherto unrecorded. Detailed tests on a large scale are at 

 present in progress, and it is expected that these experi- 

 ments may throw further light on this peculiar formation. 



SUMMARY. 



The results of the present investigation may be briefly 

 stated as follows ; 



1. Cauliflower plants sprayed with copper ammonium carbonate 

 produced large numbers of intumescences as a direct result of the 



spraying. 



2. Similar intumescences were produced by means of weak solutions 

 of copper chloride, copper acetate, copper nitrate and copper sulphate 

 when sprayed in very line drops on the surface of the leaves. 



3. The intumescences were formed in larger 'numbers on the lower 

 surface of the leaves than on the upper surface of the leaves. 



4. Intumescences were formed independent of soil or atmospheric 

 conditions, so that the heat and water supply had nothing to do with 



their formation. 



5. Intumescences must be regarded as a result of the stimulating 



activity of chemical poisons, sprayed upon the leaf in weak solutions. 



6. The stimulating activity exerted is probably due to the formation 

 of compounds within the cells of high osmotic tensions, these com- 



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