516 . S. O. MAST 



Whatever the processes within the organism may be that are 

 induced by the environment in the production of changes in the 

 sense of orientation, the same processes may, at least in part, 

 occur without any immediate action of the environment as the 

 following evidence shows. 



EFFECT OF CHANGE IX PHYSIOLOGICAL STATES 



As previously set forth, if the proper amount of acid is added 

 to a culture fluid in which Spondylomorum is negative, it becomes 

 positive, but ordinarily it remains positive only a few minutes 

 and then becomes negative again. If now fresh negative speci- 

 mens from the same culture jar are added to the solution con- 

 taining the acid, they respond just as the first specimens did when 

 the acid was added. They may be momentarily negative, but 

 they soon become positive and remain so for a few minutes, after 

 which they become negative and remain so. This is clearly seen 

 in the experiment described on page 508. 



It was observed repeatedly in other experiments. This demon- 

 strates conclusively that the reversion from positive to negative 

 orientation is not due to a change in the solution, but to a change 

 within the organism, for if it were due to a change in the solution, 

 the second lot of individuals, when added, should have responded 

 just as the first set was responding at that time. 



EFFECT OF ANESTHETICS 



As previously stated, the addition of chloroform, ether, or 

 chloral hydrate like the addition of acids causes negative colonies 

 of spondylomorum to become positive, and the reactions of th*^ 

 colonies to these substances in reference to orientation are in detail 

 essentially the same as their reactions to acids. If a trace of 

 chloroform, for example, is added to a culture solution containing 

 negative colonies, they become, iii the course of a few moments, 

 strongly positive. Then after a few minutes they become nega- 

 tive again. If now more chloroform is added, they again become 

 positive and after a few minutes again negative, etc., until the 

 chloroform becomes sufficiently concentrated to produce anes- 

 thesia. The reversion from positive to negative orientation is 



