524 FORCING THE MUSHROOM IN BRITISH GARDENS. 



condensation of the internal vapour, and which are in other respects eligible 

 for the purpose. 



" A thatched roof of a good thickness is very proper ; a slated or tiled one 

 is, on the contrary, objectionable, unless a ceiling be formed under it. If 

 the cavity between the ceiling and the external covering were filled with dry 

 moss, a more complete protection would be formed against any sudden vicis- 

 situdes of cold and heat, an object of importance towards success either in 

 the cold winter months or during the greatest heat of summer." (Penny 

 Cyc. vol. xvi. p. 19.) 



SUBSECT. II. Forcing the Mushroom in British gardens. 



1112. The ordinary form of a mushroom-house is a lean-to shed, at the 

 back of a south wall, or of a range of hothouses, about nine feet wide, eight 

 feet or nine feet high at front, and twelve feet or fifteen feet at the back. 

 Along the middle there is a path three feet wide over a flue, or hot water- 

 pipes, or in some cases a trench of two feet wide, and the same depth for a 

 bed of fermenting manure. Planks, in this latter case, are placed over the 

 dung for the purpose of walking on. The space between the walls and the 

 path is occupied by shelves of slate or flag-stone, three feet broad, eighteen 

 inches or two feet apart in the height ; each shelf having a slate or stone curb 

 nine inches deep. The manner in which mushrooms are grown in such a 

 house is as follows : 



1113. The spawn may be either made or purchased. Cake or brick spawn 

 is the sort best worth making, and the best sort of materials to make it of 

 are, equal portions of horse-droppings, cow- droppings, and loam, well mixed, 

 and pounded or beaten, adding only as much water as will bring the materials 

 to the consistency of brickmakers' moulding clay. Then let a circular mould 

 without a bottom, nine inches in diameter and three inches deep, be placed on 

 a table, with the wide end uppermost, and filled with this mortar and straked 

 level ; before it is turned out of the mould, let three holes be made in each cake, 

 with an iron-shod ^dibber, one inch and a half deep : the mould must be 

 shaped like the frustum of a cone, that the cakes may easily part with it. 

 When the cakes are all but hand dry, let them be spawned, by putting a 

 piece of spawn about the size of a pigeon's egg in each hole, inclosing it with 

 a little of the original mortar. Then pile the cakes in pairs, with their 

 spawned ends together, resembling a cask ; and in this state let them be 

 cased up in brick -shaped batches, and sweated and kept up to about 85, by 

 placing a layer of sweet dung all round and over the batch, varying it in 

 quantity, to obtain the desired heat. The spawn must be examined as it 

 runs in the cakes, and when one is broken and appears mouldy all through, 

 and smells of mushroom, it is mushroom spawn in the highest state of per- 

 fection. It must not be allowed to run so far as to form a thread-like sub- 

 stance. To preserve it, it must be thoroughly dried in an airy loft, and 

 kept dry for use. It will retain its properties for several years. 



1114. To grow the mushrooms. Collect a quantity of horse-droppings, 

 dry them a little in an open shed, then lay a stratum of loamy turf, two 

 inches or three inches deep, in the bottom of the bed, and over this three 

 layers of droppings, each about two inches deep, rendered as compact as pos- 

 sible, by giving each layer a good pummeling with a hand-mallet. When 

 the last layer is made up, thrust a few " watch sticks" into the bed, in order 

 to ascertain when it begins to heat. When the heat is getting pretty strong, 



