of the method of making tissue cultures. The use of the latter 

 method has been the means of a sudden advancement in spawn 

 making in this country during the past two years, for many prac- 

 tical men have been quick to see the advantages which it offers. 



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 pure-culture methods necessitates to a con- 

 siderable extent a knowledge of the bacteria and molds which are 

 everywhere present in the air and which are especially abundant 

 wherever there are dusty or damp, moldy conditions. 



15. The Vitality of Mushroom Spawn 



Many of the early experiments in mushroom growing under- 

 taken by the writer were made in the hope of bring able to ascer- 

 tain the more frequent cause of failure and some of the chief diffi- 

 culties encountered by American mushroom growers. The ordinary 

 commercial (English) spawn used by amateurs, that is, such as is 

 obtainable upon the market during the winter months, was pur- 

 chased wherever possible. Samples of this spawn were placed 

 under conditions which were supposed to be most favorable for 

 growth. Nevertheless, in the majority of cases there was no indi- 

 cation of the development of a new mycelium from the bricks of 

 spawn thus obtained. 



Special importations of some of the commercial English and 

 French spawns were made, and this was packed, shipped, and 

 stored under conditions as favorable as may ordinarily obtain. 

 This spawn was imported during the mid-winter and sorted until 

 March or early April, when it was used in spawning some experi- 

 mental beds. The conditions of the experiments were practically 

 the same throughout, yet in not more than half the beds was theire 

 a favorable development of mushroom spawn. 



16. The Storage of Spawn 



It is possible to ruin good spawn by improper storage, even in 

 a relatively short period of time. Spawn should be kept in a place 

 that will be both cool and dry, but never liot and dry. This should 

 be remembered by both seedsmen and growers, for many failures 

 may, undoubtedly, be attributed to the improper starage to which 

 the material has been subjected." 



From the reports of Dr. B. M. Duggar, Professor of Botany at the University of Columbia, and 

 Collaborator of the Bureau of Plant Industry, U. S. Department of Agriculture. 



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