Some Questions which they Suggest. 25 



world as well as in the social affairs of man. How, one 

 cannot help asking, is the plasmodium made aware .of the 

 proximity of its appropriate food ? Has it some rudimen- 

 tary perception some common sense, of which sight, and 

 smell, and taste are only more specialized forms ? What 

 the plasmodium does in the equally near presence of two 

 equally attractive morsels we do not know ; but we do not 

 believe that it would starve. 



Sunshine is, again, a condition which seems to exert 

 an influence on the movements of plasmodia. If a glass, 

 on which the network of a plasmodium ia spread, be partly 

 exposed to the sunlight, it hag been observed to withdraw 

 to the shaded parts, and yet when the time comes for 

 the sporangia to be produced it would seem in some species 

 as if there was a movement towards surfaces exposed to 

 light. But, according to the observations of Mr. Lister, 

 light apart from direct sunshine does not affect the 

 movements of plasmodia. 



The plasmodium has been found to be sensitive not 

 only to sunlight, to dampness and dryness, to heat and 

 cold, but to the influence of chemical substances : the 

 weak solutions of some chemicals having been observed to 

 render it more fluid, whilst stronger solutions of the same 

 substances have made it contract or perish in parts. This 

 sensitiveness on the part of the plasmodia to so many 

 influences must, it would appear, render very delicate the 

 conditions under which alone myxies can succeed in the 

 struggle for existence. Furthermore, it would appear that 

 in the selection of places for the production of the sporangia 



