MUSUROOM SPAWN MAKING. 58 



.[(/arkus rampestris, but also sonic of its varieties. In Elnglaiul 

 much of the virgin spawn has been obtained from pastures. Where a 

 •• spontaneous "' growth of spawn is observed, trenches are dug, and 

 these are filled with good stable manure. The latter in time becomes 

 penetrated, and it is highly prized for cultural purposes. As a rule, 

 rhe virgin spawn is used in spawning beds, which, when well pene- 

 trated, are torn down, and the whole bed used as flake spawn in 

 spawning the general croj). Again, the virgin spawn may be used 

 in spawning the brick, or cakes, this being the form in which English 

 spaAvn is usually made. However adept persons may become in the 

 identification of various varieties of spawn by odor, etc., this must 

 be considered essentially a chance method. 



A " selective " method. — From what has been said it will be per- 

 ceived that very little advancement could be made in the selection of 

 desirable varieties of mushrooms, in varietal improvement and the 

 like, so long as the chance method of securing spawn should prevail. 

 The studies in the germination of mushroom spores previously re- 

 ferred to were encouraged by the apparent necessity of beginning 

 with spores from mushrooms of known qualities in order to effect 

 improvement. In recent years the investigations of Costantin « upon 

 spore germination have found application in a department of the 

 Pasteur Institute. Bv a secret method, mvcelium is grown from the 

 spores in jjure cultures. These cultures, which are, of course, pure 

 virgin spawn, are then offered for sale to the gi-owers. This spawn 

 does not seem to have received deserved consideration on the part of 

 the growers. The secret method of effecting spore germination re- 

 ferred to by Repin 'J has also been practically applied by one of the 

 largest seed firms in Paris. In general, however, French growers 

 have not profited so much by the new methods, perhaps partially on 

 account of the fact that these methods are not known and partially 

 because of the expense of the new virgin spawn. It is to be noted 

 that these methods imply pure cultures to begin with. 



The successful germination studies with chemical stimulation men- 

 tioned in this paper were soon overshadowed by the discovery of the 

 ease of makinsr tissue cultures. The use of the latter method has 

 ])een the means of a sudden advancement in spawn making in this 

 country during the past tAvo years, for many practical men have 

 been quick to see the advantages which it offers. 



Pure-culture precautions. — It has already been stated that the 

 pure-culture method of making virgin spawn is not one which will 

 prove successful in the hands of wholly inexperienced persons, or of 

 those who are unwilling to spend time and use the utmost care in the 

 manipulation of the cultures and the culture material. The use of 



a Costantin, J., loc. cit ^ Ri'pin, C, loc. cit. 



