380 Scientific Proceedings, Royal Dublin Society. 



It was probably only by chance that no diseased seedlings appeared from 

 the seed steeped for two minutes in hydrogen peroxide. Steeping for several 

 minutes in this solution did not entirely eliminate the disease, but reduced it 

 to small limits and had practically no adverse effect on germination. It was 

 particularly noted that the use of hydrogen peroxide had no deleterious effect 

 on the development of the seedlings. 



Of the two disinfectants, formalin would be the cheaper, hut hydrogen 

 peroxide would be safer and equally efficient, if allowed to act for a con- 

 siderable time. Neither of these two solutions is, however, perfectly 

 satisfactory ; and, in fact, any solution in which water is the solvent is 

 disadvantageous for treating flax-seed, owing to the caking together of the 

 seeds which is bound to occur more or less, and the difficulty of drying them 

 again satisfactorily and without injury. 1 



In view of this difficulty, an attempt was made to disinfect the seed with 

 liquids other than watery solutions. For this purpose, infected seed was 

 steeped for half a minute in methylated spirit, allowed to dry, and then sown 

 in sterilized soil. This treatment did not in any way impair the germination 

 of the seed or injure the seedlings arising from it, but it had no effect what- 

 ever in suppressing the disease. Probably the time of steeping was so short 

 that neither the interior of the seed nor the dormant mycelium in its epidermis 

 was reached by the spirit. 



Trials were also made with two proprietary fluids, sold for treating seed 

 grain, primarily for the purpose of preventing the depredations of birds, but for 

 which it has also sometimes been claimed that they are effective in preventing 

 " smut " and " bunt." These liquids are of a more or less oily character, and 

 appear to be coal-tar products. Steeping infected flax-seeds for one minute 

 in these liquids, however, did not give satisfactory results. The seedlings 

 produced were somewhat retarded in growth ; their cotyledons were scorched 

 by coming into contact with the se'ed-coats, while there was little or no 

 reduction in the number of seedlings which became diseased. 



In another experiment seeds were coated with the moist precipitate pro- 

 duced by mixing solutions of copper sulphate and washing soda, as is done in 

 the preparation of potato- spraying mixture. There was no ill effect on germi- 

 nation or on the resulting seedlings. The percentage of diseased seedlings 

 was considerably reduced, but not to the vanishing point. 



'. In some parts of the United States of America it is regarded as absolutely essential 

 to disinfect flax-seed before sowing, to ward off attacks of "wilt" (Fusarium). It is 

 recommended to throw a fine misty spray of formaldehyde solution (1 lb. to each 

 40 gallons (U.S.A.) of water) over the seed, this being meanwhile shovelled and raked 

 over. Half a gallon of solution is sufficient for a bushel of seed. 



