SLUGS AS MYCOPHAGISTS 223 



wet evening in August, 1897, at Clifton, Derbyshire, saw a Limax 

 maximus crawling directly toward a plate upon the lawn, contain- 

 ing the remains of the dog's dinner ; when first observed the slug 

 was about six feet distant from the plate, but within thirty minutes 

 had reached it ; the plate was then removed to a second position, 

 about six feet away, but in another direction ; the slug almost 

 immediately changed its course, and again made straight towards 

 the plate, on again nearing it the same process was repeated with 

 the same result, the plate being finally removed and placed in a 

 fourth position, eight feet away, and directly to the leeward of the 

 slug, yet in a little more than half-an-hour the slug had reached 

 the plate." 



Ernst Stahl l of Jena, whilst carrying out some extended 

 investigations upon the chemical and physical means by which 

 certain plants are protected from the attacks of slugs and snails, 

 incidentally convinced himself by experiment that slugs find their 

 way to their food by their sense of smell. He placed a slug (Limax) 

 upon a moistened dinner plate and with his mouth blew gently 

 upon it in a horizontal direction. He found that the current of 

 air so produced had no particular effect upon the slug's movements. 

 He then put a cup fungus, Peziza vesiculosa, between his mouth 

 and the slug and continued blowing. The slug then immediately 

 changed its behaviour. If the slug's head had been turned away 

 from the experimenter, the slug raised it, moved its tentacles 

 about in the air, soon turned the front part of its body around, and 

 then steered, as the blowing continued, straight toward the fungus. 

 That the slug sought its food by its sense of smell and not by its 

 sense of sight, Stahl showed as follows. He blew over the Peziza 

 as before and waited until the slug had approached to within about 

 1 cm. of its surface. He then took another Peziza, placed it upon 

 the opposite side of the plate, and blew over it toward the slug. 

 The new current of air was thus made to move in the opposite 

 direction to the first one and to pass over the second fungus, the 

 slug, and the first fungus successively. Stahl then observed several 

 times that the slug, although only 1 cm. away from the first fungus 



1 Ernst Stahl, Pflanzen und Schnecken, Sine biologische Studie uber die 

 Schutzmittel der Pflanzen gegen Schnecken frass. Jena, 1888, foot-note, pp. 15-16. 



