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The Country Gejitleman's Magazine 



kind of exhalations from damp, unventilated 

 ground, with some disturbed magnetic state of 

 the earth and air. These adjuncts are as neces- 

 sary as the sugar in the sweet wort used for the 

 production of beer, or the absence of ventilation 

 for the production of dry rot. 



The tuber is planted with the " resting spore " 

 in its eye ;. it sends up its haulm with the spore 

 in its tissue. Just about the time of flowering 

 the juices in the plant are matured sufficiently 

 for the " resting spore " to devclope ; if then 

 there should be the conjunction of circum- 

 stances I have mentioned, viz., moisture, un- 

 drained ground, and electric disturbances, with 

 luxuriant tops to the plants, the fungus is deve- 

 loped in the most marvellous manner, and 

 millions of spores are wafted over the field, not 

 resting, but immediately growing, sending their 

 mycelium into the stomata, or breathing pores, 

 upon the plant, and in a few hours poisoning the 

 whole of the crops by interfering with the proper 

 maturation of the juices. Every potato receiving 

 juice from a diseased haulm will suffer. 



The growth of the fungus arises from its ab- 

 stracting an important part of the juice of the 

 plant, so that the character of the circulating 

 fluid is quite altered ; and a similar result hap- 

 pens as is the case when a human being is 

 deprived of the oxygen required for active 

 respiration, or if some other gas is respired. 

 The blood is altered, and if the alteration is con- 

 tinued long enough, death results. No doubt 

 highly-manured lands and crops dressed with 

 artificial manures beyond measure more easily 

 succumb to the disease, just as is the case with 

 highly-fed, richly-seasoned human beings, when- 

 ever fever gets hold of them they rot most 

 rapidly. So also if plants are infested with 

 insects, such as the Eupteryx picta, they will 

 more easily yield to the disease because they 

 contain less mineral matter in their tissues ; but 

 such are not causes for the disease. The cause 

 is the fungus Botrytis infestans. The remedy 

 is to destroy the germ before planting, and 

 so to treat the seed that no fungoid growth 

 shall be possible while stored away. Care 

 should be taken to pick out the best specimens 

 for seed— middle-sized, undeformed, and clear- 

 skinned tubers — which is so often contrary to 

 the general custom. These should then be 



treated with a dressing of some material which 

 prohibits fungoid growths, such as chloralum, 

 preparations of carbolic acid, or creosote, and 

 then stored in a dry, well-ventilated chamber, 

 where the temperature shall range between 35 

 deg. and 45 deg. If they shew signs of sprout- 

 ing they should be immediately planted, for the 

 removal of the early sprouts takes away much 

 of the mineral matter out of the tuber. Common 

 sense will dictate the measures which should 

 be taken for the proper ventilation and drainage 

 of the soil in which they are planted. If these 

 rules are carried out, I feel convinced that the 

 disease will be reduced to a minimum, and a 

 general epidemic be seldom possible ; at the 

 same time, seedlings and fresh soil appear to 

 me to be as necessary as in every other kind of 

 cropping. 



I write these suggestions in the belief that 

 one law governs the action of disease, whether 

 in plants or in human beings, and that it is 

 easier to destroy the " resting germs " than to 

 stay their effects. It may be urged against this 

 view that the tubers used for seed could be 

 destroyed by the germ in the eye, but it is one 

 of the points in the natural history of the 

 Botrytis infestans that it feeds upon the juices 

 of the growing plant, and the matured potato is 

 not growing, therefore the concurrent circum- 

 stances requisite for its fertile development are 

 not present. The " resting spore " continues 

 such until all the circumstances are favourable 

 for its grovvth. It is carried upwards in the 

 haulm until its proper season arrives. This 

 may not come ; it may be too dry, or there may 

 be no magnetic disturbances, or these changes 

 may come too late — then no epidemic. 



I should mention that after the tuber has 

 been infested by the Botrytis, its destruction is 

 completed by another fungus, the Fusisporium 

 Solanii, which changes its form as the work of 

 destruction proceeds, hardening some portion 

 of the tissue of the potato, but changing the 

 major part into a gelatinous, stinking mass, by 

 means of which the starch is destroyed, while 

 the gluten and the juices proper appear to be 

 the food upon which the Botrytis flourishes.. 

 If, therefore, Dr Hooker's suggestion be carried 

 out for saving the starch, it must be done before 

 the Fusisporium is developed. 



