CiiAP. XI. MEANS OF DISPERSAL. 833 



But seeds 111:13' l)c occasionally transported in another man- 

 ner. Drift-timber is thrown up on most islands, even on those 

 in the midst of the widest oceans; and the natives of the 

 coral-islands in the Pacific procure stones for their tools, solely 

 from the roots of drifted trees, these stones being a valualjle 

 royal tax. I find, on examination, that, when irregularly- 

 shaped stones are embedded in the roots of trees, small parcels 

 of earth are very frequently enclosed in their interstices and 

 behind them — so perfectly that not a particle could be washed 

 away in the longest transport : out of one small portion of. 

 earth thus completely enclosed by wood in an oak about 50 

 years old, three dicotyledonous plants germinated : I am cer- 

 tain of the accuracy of this observation. Again, I can show 

 that the carcasses of birds, when floating on the sea, sometimes 

 escape being immediately devoured ; and seeds of many kinds 

 in the crops of floating birds long retain their vitality : peas 

 andvetches, for instance, are killed by even a few days' immer- 

 sion in sea-water ; but some taken out of the crop of a pigeon, 

 which had floated on artificial salt-water for 30 days, to my 

 surprise nearly all germinated. 



LiWng birds can hardly fail to be highly-effective agents in 

 the transportation of seeds. I could give many facts showing 

 how frequently birds of many kinds are bloAvn by gales to vast 

 distances across the ocean. We may safely assume that undei" 

 such circumstances their rate of flight would often be 35 miles 

 an hour ; and some authors have given a far higher estimat'C. 

 1 have never seen an instance of nutritious seeds passing 

 through the intestines of a bird ; but hard seeds of fruit pass 

 uninjured through even the digestive organs of a turkey. In 

 the ctHirse of two months, I picked up in my garden 12 kinds 

 of seeds, out of the excrement of small birds, and these seemed 

 jierfect, and some of them, which were tried, germinated. But 

 the following fact is more important : the crops of birds do iif)t 

 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 tli<? 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 cxperi- 



