April 1, 1896.] 



KNOWLEDGE. 



79 



animals, one small place only being soft for the embryo 

 plant to push through. 



An interesting fact maybe mentioned here, showing the 

 possibility of the conversion of a deterrent into an attrac- 

 tive i'ruit, for Darwin states that there is considerable 

 evidence to show that the peach has been derived from the 

 almond by artificial selection. 



Let us now consider the origin of fruits. The doctrine 

 of natural selection tells us that, in uncultivated plants 

 in a state of nature, no part can be present that is not of 

 direct use to the plant ; and in the 

 case of fruits, no part can be present 

 that is not directly concerned with 

 the preservation and dispersal of its 

 seeds. Hence it is absurd to suppose 

 that fruits were created for man's 

 special benefit, for, in the first place, 

 fruits are abimdant in parts of the 

 world where man is seldom or never 

 seen ; and secondly, if man were the 

 chief eater of fruits, such fruits 

 would soon disappear, for their seeds 

 would not be sutHciently dispersed 

 or deposited in suitable places for 

 germination. 



In fact, the origin of fruits fur- 

 nishes us with some of the best 

 examples of the doctrine of natural 

 selection, for in the case of plants 

 we at once get rid of the idea of 



voluntary action, so ditlicult to escape in the case of 

 animals. We are apt to imagine an animal consciously 

 striving to better itself in the struggle for existence, but 

 with plants this predisposition is avoided, as we should 

 never imagine a fruit striving consciously to make itself 

 more succulent. 



First let us discuss the origin of attractive fruits. All 

 succulent fruits were not originally alike ; some happened 

 at one time to be sweeter than others, owing to an 

 accidental deposit of sugary matter m the tissues. These 

 were at once eaten by birds and the more sour ones 

 rejected ; hence the sweet ones survived, and their seeds, 

 having been uninjured by digestion, became dispersed, 

 and gave rise to others which reproduced the characters 

 of their parents. The most attractive of these were again 

 eaten, and survived ; and so on, generation after generation, 



Fig. 4. — Diagram of 

 Fig, showing invaginatefl 

 rct-eptaule lined willi 

 Auhencs. 



Fig. C. — Diagram of Apple, showing succulent calyx and mesocarp, 

 and fibrous epicarp and endocarp. 



the fruits becoming more and more succulent, because the 

 succulent ones only survived, in this group of fruits. 

 This process may be carried still further by artificial 

 selection, so that the original object of the fruits is lost, 

 and fruits can be produced which have no seeds. In this 



way finer fruits are produced, as the nutriment, originally 

 intended for the seed, goes to increase the supply forthe fruit. 



We should naturally expect that attractive fruits did 

 not appear on the earth till there were animals which 

 would eat them ; both must have developed simultaneously, 

 and in mutual dependence on each other. So we find no 

 traces of succulent fruits even in so late a geological 

 formation as that of the lias or cretaceous clift's, for the 

 simple reason that there were no animals to eat them, 

 the birds of that period being carnivorous, while the 

 mammals were mostly primeval kangaroos or savage 

 marsupial wolves. It is only in the modern tertiary 

 period that we find the earliest traces of the rose family, 

 the greatest fruit-bearing tribe of our modern world. 



The origin of the deterrent fruits is the exact opposite 

 of that of the attractive fruits. The seeds of these were 

 stored with food for the young plant, and were exposed to 

 the attacks of birds, monkeys, and other animals. Since 

 no two fruits were exactly alike, some happened to have 

 a harder or more bitter shell than the others ; these were 

 consequently avoided, and so survived. The hungrier 

 their foes, the more need was there for protection, and so 

 the hardness and bitterness of the shell went on increasing 

 from generation to generation, for only the hard and bitter 

 ones survived. The nut which best survives on the 

 average is that which is the least conspicuous in colour, 

 has a rind of the most objectionable taste, and is enclosed 

 in the hardest shell. 



Thus there is in nature a continuous battle between plants 

 and the animals which feed upon them, those animals 

 only surviving which manage to overcome the protective 

 devices of plants, and those plants only surviving 

 whos3 protection is good enough to defy the attacks of 

 animals. 



THE WHITE-BREASTED ALBATROS ON 

 LAYSAN ISLAND 



THE Hon. Walter Rothschild is well known as a keen 

 and energetic worker in the cause of science, but 

 the greater number of our readers are perhaps 

 unaware of how much he has done in bringing 

 new species of birds to light, by means of his 

 collectors in all parts of the world. 



It is now some four years ago that Mr. Rothschild sent 

 out a collector — Henry Palmer — to explore the small 

 islands and sandbanks scattered about in the Pacific Ocean 

 in a north-westerly direction from the Sandwich Islands. 



Up to that time, these islands were virgin land to the 

 ornithologist. The discovery, however, by Henry Palmer 

 of many species of birds perfectly new to science fully 

 justified Mr. Rothschild in deciding to have these out-of- 

 the-way reefs ornithologically explored. 



By far the most interesting island of the group is Laysan 

 or Moller Island, a small stretch of land about three miles 

 long and two and a half broad, surrounded by a reef, and 

 having in it a salt lagoon of some one hundred acres in 

 extent. It is covered with a luxuriant growth of coarse grass 

 and of low shrubs, and possesses a few pigmy palms. There 

 are a few huts on it, and it is occupied by a guano company. 



The island literally swarms with birds. An idea of 

 their enormous numbers may be gathered from Palmer's 

 own words on the first day he spent on Laysan : — 



" I have seen so many birds, and have been so excited, 

 that I must leave my description of them till I have seen 

 more at my leisure." 



The most numerous bird on the island is the white- 

 breasted albatros, or the gooney {Dimnedea iniinutahilis 



