CHAP. XII.] MEANS OF DISPERSAL. 307 



of small birds, and these seemed perfect, and some of them, which 

 were tried, germinated. But the following fact is more impor- 

 tant : the crops of birds do not secrete gastric juice, and do not, 

 as I know by trial, injure in the least the germination of seeds ; 

 now, after a bird has found and devoured a large supply of food, 

 it is positively asserted that all the grains do not pass into the 

 gizzard for twelve or even eighteen hours. A bird in this interval 

 might easily be blown to the distance of 500 miles, and hawks are 

 known to look out for tired birds, and the contents of their torn 

 crops might thus readily get scattered. Some hawks and owls 

 bolt their prey whole, and, after an interval of from twelve to 

 twenty hours, disgorge pellets, which, as I know from experiments 

 made in the Zoological Gardens, include seeds capable of germina- 

 tion. Some seeds of the oat, wheat, millet, canary, hemp, clover, 

 and beet germinated after having been from twelve to twenty-one 

 hours in the stomachs of different birds of prey ; and two seeds of 

 beet grew after having been thus retained for two days and 

 fourteen hours. i'resh-water fish, I find, eat seeds of many land 

 and water plants ; fish are frequently devoured by birds, and thus 

 the seeds might be transported from place to place. I forced 

 many kinds of seeds into the stomachs of dead fish, and then gave 

 their bodies to fishing-eagles, storks, and pelicans ; these birds, 

 after an interval of many hours, either rejected the seeds in 

 pellets or passed them in their excrement ; and several of these 

 seeds retained the power of germination. Certain seeds, however, 

 were always killed by this process. 



Locusts are sometimes blown to great distances from the land ; 

 I myself caught one 370 miles from the coast of Africa, and have 

 heard of others caught at greater distances. The Rev. E. T. Lowe 

 informed Sir C. Lyell that in November 1844 swarms of locusts 

 visited the island of Madeira. They were in countless numbers, 

 as thick as the flakes of snow in the heaviest snowstorm, and ex- 

 tended upwards as far as could be seen with a telescope. During 

 two or three days they slowly careered round and round in an 

 immense ellipse, at least five or six miles in diameter, and at 

 night alighted on the taller trees, which were completely coated 

 with them. They then disappeared over the sea, as suddenly as 

 they had appeared, and have not since visited the island. Now, 

 in parts of Natal it is believed by some farmers, though on insuffi- 

 cient evidence, that injurious seeds are introduced into their grass- 

 land in the dung left by the great flights of locusts which often 

 visit that country. In consequence of this belief Mr. Weale sent 

 me in a letter a small packet of the dried pellets, out of which I 

 extracted under the microscope several seeds, and raised from 

 them seven grass plants, belonging to two species, of two genera. 

 Hence a swarm of locusts, such as that which visited Madeira. 



n* 



