Larval Dimorphism 



the larva of the Anthrax, it suggests rather 

 some microscopic Thread-worm that, by acci- 

 dent, has made its way through the skin of its 

 host and come to enjoy itself outside. I do 

 not reckon my discovery as of much value, 

 because I am so greatly puzzled by the crea- 

 ture's appearance. No matter: we will take a 

 small glass tube and place inside it the 

 Chalicodoma-grub and the mysterious thing 

 wriggling on the surface. Suppose it should 

 be what I am looking for ? Who knows ? 



Once warned of the probable difficulty of 

 seeing the animalcule for which I am hunting, 

 I redouble my attention, so much so that, in a 

 couple of days, I am the owner of half a score 

 of tiny worms similar to the one which caused 

 me such excitement. Each of them is lodged 

 in a glass tube with its Chalicodoma-grub. 

 The infinitesimal thing is so small, so diapha- 

 nous, blends to such good purpose with its host 

 that the least fold of skin conceals it from my 

 view. After watching it one day through the 

 lens, I sometimes fail to find it again on the 

 morrow. I think that I have lost it, that It 

 has perished under the weight of the over- 

 turned larva and returned to that nothing to 

 which It was so closely akin. Then it moves 

 and I see it again. For a whole fortnight, 



