22 THE STORY-BOOK OF SCIENCE 



Openings are made for the service of the sheepfold. 

 The chalet is finished. Its inmates enjoy cool and 

 quiet, with an assured supply of provisions. What 

 more is needed for happiness ? The cows are there, 

 very peaceful, at their rack, that is to say, fixed by 

 their suckers to the bark. Without leaving home the 

 ants can drink to satiety that sweet milk from the 

 tubes. 



* ' Let us say, then, that the sheepfold made of clay 

 is a building of not much importance, raised with 

 little expense and hastily. One could overturn it by 

 blowing hard. Why lavish such pains on so tempo- 

 rary a shelter ! Does the shepherd in the high moun- 

 tains take more care of his hut of pine branches, 

 which must serve him for one or two months ? 



"It is said that ants are not satisfied with inclos- 

 ing small herds of plant-lice found at the base of a 

 tuft of grass, but that they also bring into the sheep- 

 fold plant-lice encountered at a distance. They thus 

 make a herd for themselves when they do not find one 

 already made. This mark of great foresight would 

 not surprise me ; but I dare not certify it, never hav- 

 ing had the chance to prove it myself. What I have 

 seen with my own eyes is the sheepfold of the plant- 

 lice. If Jules looks carefully he will find some this 

 summer, when the days are warmest, at the base of 

 various potted plants." 



"You may be sure, Uncle," said Jules, "I shall 

 look for them. I want to see those strange ants' 

 chalets. You have not yet told us why ants gorge 

 themselves so, when they have the good luck to find 

 a herd of plant-lice. You said those descending the 



