34 MUSHROOM GROWING AND SPAWN MAKING. 



'' fermentation " is of itself a minor matter. In j)ure ciiltnres, Avhere 

 sterile media are employed, mushroom, spawn starts slowly, but 

 finally grows best, in general, upon fresh (wholly unfermented) 

 manure. It grows least well. or. rather, less densely, so far as tested, 

 on very well fermented manure. This certainly indicates that it is 

 not fermentation Avhich is ordinarily advantageous. In practical 

 nnishroom growing, however, it is not possible to deal with ])ure cul- 

 tures; and, therefore, other conditions of the environment must be 

 correspondingly changed. The rapid oxidation action of bacteria, 

 and perhaps of independent ferments, upon manure causes a consid- 

 erable rise of temj^erature. At the higher temperatures (which 

 uuiy be maintained as long as there are present rapidly oxidizable 

 food products) bacterial action is vigorous, and is unquestionably 

 injurious to mycelial development. Wholly aside from the rise of 

 temperature accompanying their activities, bacteria are otherwise 

 injurious. In fact, manure which is ])ut to ferment in a small test 

 tube shows little or no rise of temperature above that of the place in 

 which it is incubated. Nevertheless, the mycelium of the mush- 

 room will not grow under such conditions. Rapid bacterial action 

 is therefore i)rejudicial. Under those conditions where bacterial 

 action is not rapid, fresh manure might be used to advantage; in 

 other words, if the beds are so constructed that the manure ferments 

 very gradually, without either excessive bacterial action or rise of tem- 

 perature, then spawning might be made in fresh manure. 



The old belief that rotten manure does not have the necessary 

 strength — that is. does iu)t produce so ^'igoro^ls a mushroom growth 

 as that which has been less transformed V)y bacterial action — has been 

 confirmed by practical experiments. This loss of effectiveness is 

 probably due, in part, to a change in texture or to other physical 

 changes. In well-rotted manure there is am])le food material to sup- 

 port a very good growth of mycelium in i)ure cultures. This has 

 been chemically proved by sterilizing such manure and growing mush- 

 room spawn upon it in pure culture. Nevertheless, by comparing 

 (in Table VIII) No. 12 with Nos. 13, 14, and 15, it will be seen that 

 beds prepared with well-fermented manure and left foi- some time 

 before si)awning do not yield so well. It is believed that here the 

 physical condition has nnich to do Avitli the result. 



The latter does not by any means invalidate the following practice, 

 which has commended itself to some veiy successful growers: The 

 maiHire is piled in very large compost heaps, where it is kei)t moist 

 and is turned only once or twice. It ferments very slowly. Then it 

 is carted into the cave, or mushroom house, long before it could be 

 considered in ]>roi)er condition to be s})awned. The l)eds ( usually 

 flat when this is the procedure) are made immediately. -These are 

 fairly well moistened and com2)ressed, then left to undergo a gradual 



