58 ANIMAL INTELLIGENCE. 



seeing their predicament, went back, bringing with them 

 aphides which they kept sticking into the tar until a 

 clear bridge was made, when they passed the obstruction 

 in safety. This indicates that while the ants value their 

 aphides very highly, they will yet part with them, if 

 necessary, for their own safety — as the captain and crew 

 of a vessel in distress will throw over the cargo, to save 

 the ship from sinking. 



The "Driver Ants," of South America, display extra- 

 ordinary intelligence in crossing streams. When one of 

 these is encountered on the march, the column halts and 

 the captains go ahead to explore. If a tree is found 

 whose overhanging boughs arch the stream, they cross 

 over on that, promptly falling into line on the other 

 side. If no such natural bridge is discovered, they will 

 examine the shore until a sandy beach is found, when 

 each ant will seize a piece of wood, mount it, and push 

 out, keeping hold with their feet, and with their paws 

 make fast to the one in front. When this floating bridge 

 becomes so long that they can no longer keep it together, 

 a portion of it breaks away and the little boats drift over 

 to the other shore. New ones are then launched until 

 the entire army has passed over. This story, as well as 

 the others which I have narrated, are vouched for by 

 separate and independent observers, and can be relied 

 upon. They are conclusive, I think, of the fact that ants 

 possess not merely highly endowed instincts, but an in- 

 telligence associated with reason, which enables them to 

 adapt themselves to new conditions, when such adapta- 

 tion is of value to them in the struggle for existence. 



The marvelous mechanical ingenuity displayed by bees 

 in the construction of their hives is well known. " The 

 cell of the hive bee," says one, " exhibits the most perfect 

 form of architecture to economize space and material 

 that can be devised. It is built on geometrical principles 

 — the lines at the bottom of each cell converge exactly 



14: 



