Curtis : Turgidity in Mycelia 13 



that it controls growth nor, on the other hand, is it controlled 

 by growth, but it must sustain a certain fixed relation and come 

 into harmony with the other existing forces and conditions before 

 growth is possible. 



The more important features of the work may be summarized 

 as follows : 



1. The hyphae of fungi possess remarkable powers of adap- 

 tation but show considerable individuality in this respect. 



2. The turgidity t varies under uniform conditions. 



3. The moment of recovery from a change of concentration 

 can be accurately noted since it is indicated by an apical enlarge- 

 ment preceding the elongation of the hypha. 



4. Changes from a low to a higher conception of the sub- 

 stratum resulted in a steadily increasing period of recovery in pro- 

 portion to the concentration of the substratum. 



5. Recovery from a change from a higher to a lower concen- 

 tration was controlled only to a limited extent by the degree of 

 concentration. But there was also to be observed an individuality 

 peculiar to the genus employed which brought about these changes 

 in shorter or longer periods of time. 



6. The turgidity of a plant recovering from a change of con- 

 centration is the same as that of a plant germinated and growing 

 in the concentration to which the trial plant has been changed. 



7. Turgidity appears to be a regulatory force. 



