Sewage Irrigation at Bishop's Storlford. 



375 



flooding. For though the cost of prepara- 

 tion at Aldershott was ^40 to ^50 per acre, 

 and that for Merthyr Tydfil is said to have 

 been very much more, the work at Bedford, 

 including the covered earthenware pipes, was 

 executed for ^10 per acre; and from the 

 experience at Lodge Farm, Barking, at Mr 

 Hope's Breton Farm, near Romford, and at 

 other places, the average expense of laying 



out may be considered to be about J[^\^ per 

 acre. But there is this important considera- 

 tion — the lead remains at all times market- 

 able at about three-fourths its original value ; 

 and, what is a great saving, no manual labour 

 or attention is required to keep the field 

 apparatus in order as with carriers, gutters, 

 drains, stops, hatches, &c., in overflow irri- 

 gation. 



THE POTATO DISEASE, 



THE following is Dr Carpenter's opinion 

 about the potato disease : — The large 

 number of letters and reports upon the potato 

 disease which you have published shews the 

 deep interest which attaches to that matter. 

 Most of the reporters appear to me to have 

 missed the mark as to the cause. They cannot, 

 therefore, recommend the proper remedy for its 

 prevention in future years, while many of the 

 suggestions which have been made, if acted 

 upon, will certainly increase the evil on future 

 occasions. Some writers even throw doubt upon 

 the fungoid origin of the disease, but all practical 

 observers are convinced that it is really due to 

 the fungus Botrytis infestans, or as iome choose 

 to call it, the Peronaspora infestans, for the 

 same fungus is known by both names. The 

 fungus is allied to the Botrytis Bassiano, which 

 produced the epidemic among silkworms a few 

 years ago, called Muscardine. 



Before we can possibly point out a satisfactory 

 remedy for the disease, it is requisite to know 

 something of the natural history of its producers. 

 If the natural history of the family is properly 

 understood, it will at once be seen how useless 

 are many of the suggestions which I various 

 writers have made in your columns. 



First, there is really no difficulty in procuring 

 fungoid growths at any time and in any place, 

 provided the requisite factors are present, viz., 

 the proper degree of moisture, of heat, of food, 

 and the atmospheric conditions required for the 

 germination of the sporangia, which abound in 

 our atmosphere. In the majority of instances 

 the germs will be forthcoming, and will soon 

 give ocular proof of their existence, though they 

 themselves may be invisible. Whether it be 

 the dry rot (Merulius lachrymans) — which has 



just made its appearance among the new timbers 

 of Croydon Church, because the necessity for 

 proper ventilation was ignored— or whether it 

 be the Torula cerevisia;, which provides for us 

 our malt liquor— or the Botrytis infestans, which 

 destroys our potatoes, the effects will be pro- 

 duced if the whole of the requisites are in con- 

 junction. The architect who neglects ventila- 

 tion will introduce the Merulius lachrymans with- 

 out being required to plant the germ ; the brewer 

 will not get a properly fermented liquor unless 

 his arrangements are right as to sugar and tem- 

 perature—while the potato-grower will lose his 

 crops every few years unless he takes means to 

 keep the germs of the disease away from his 

 seed. 



The present custom of storing the seed is at 

 the root of the matter, as far as a general epide- 

 mic is concerned. It is well known to fungo- 

 logists that fungi have their times and seasons 

 as well as other plant growths, and that certain 

 spores exist, which are called " resting spores," 

 from their custom of biding their time and 

 coming to maturity when the season for their 

 development is present, remaining uninjured by 

 changes of temperature and by considerable 

 changes of their physical state, and which are 

 not destroyed unless an actual chemical change 

 is produced in them. 



These " resting spores " are produced in 

 abundance in the places in which seed-potatoes 

 arc ordinarily stored ; they bury themselves in 

 the eye of the potato, and are planted with it. 



These spores will not produce mycelium or 

 spawn, unless the proper juices are ready for 

 their development, and not then, unless the 

 physical agencies are also at hand— such as a 

 proper degree of moisture, heat, and the proper 



