Vol. XVII. No. 417. 



THE AGKIOULTirjtAL NEWS. 



123 



parts of the world. The higher domestic animals, such 

 as horses, cattle, sheep, and goats are not often annoyed 

 by fleas, but pigs may be infested to some extent. 



It has been found that fleas differ considerably in tlie 

 intimacy with which they are associated with their hosts. 

 Slime species remain on their hosts practically all the time, 

 while others are merely pas.sing guens. For instance, the 

 chigoe flea or 'jigger' {Dermatopliilu!: penetnins) ordinarily 

 buries itself in the skin of its host and there reaches maturity, 

 develops its eggs, and dies. The sticktight flea or chicken 

 flea (Echidnophaga gallin-.xcciis) spends the greater part of 

 its life attached to its host, but does not penetrate the 

 skin of the animal. Poultry are attacked chiefly on the heid, 

 about the eyes, comb and wattles, while dogs and cats may 

 be infested with this flea about the ears, mainly a'ong the 

 edges. Dog and cat fleas pass most of their adult existence 

 on their hosts, but do not attach themselves, and feed only at 

 intervals. Tlie human flea spends very little time on man, 

 the rest of its existence being passed elsewhere, mainly on the 

 floor. 



Life-Ill sto)y. The fiea, like many other insects, passes 

 through four distinct stages — the egg, larva, pupa, and adult. 

 Usually the eggs are laid by the adult female flea while on 

 the animal host, but since they are not stuck to the hair or 

 feathers, they usually fall out in the resting place or nest of 

 the animal. Fur instance, numbers of the minute, whitish 

 eggs may sometimes be seen on mats or cushions slept on by 

 infested cats or dogs. These eggs can easily be seen on dark- 

 coloured cloths. The eggs are also scattered about on the 

 flcior, and the hatching larvjf or maggots feed on the dust 

 refuse under carpets or matting, and in cracks. Fleas alsi > 

 breed outside where animals sleep beneath houses. During 

 the period of growth the skin is moulted two or three times, 

 add then the full-grown larva spins a cocoon in which it 

 passes the pupa or resting stage. 



The length of the life-cycle varies considerably with 

 different species of fleas, and under different conditions of 

 temperature, moisture, food, etc IJainfall and the amount of 

 air moisture have a great influence on flea breeding. Frequent 

 rains and a high humidity favour the production of these 

 insects, while a hot dry spell tends to check them. This does 

 not mean that fleas require very moist places in which to 

 breed, on the contrary, excessive moisture is as harmful to 

 them as excessive dryness. 



In the tropics, or under favourable summer conditions the 

 life cycle of the dog flea may be completed in from seventeen 

 to thirty-seven days, while in cool weather or under unfav- 

 ourable conditions the period fmrii egg to adult may occupy 

 considerably over a year. 



The adult flea under ordinary summer conditions does 

 not live very long without food, the life of the human flea 

 probably averaging two months, that of the dog flea some- 

 what less, and that of the chicken fle§i still less. 

 ( I'd lit' cmitliiiietl:^ 



J.C.H. 



VEGETABLE OIL. 



Staple supplies of food have, as we all know, been 

 seriously affected by the war, :tnd there have been much 

 shifting of sources of supply an<l evolution of new material. 

 One of the most striking instam es of the foregoing is the 

 supply of fat and oil. L'p to the beginning of the war the 

 use of animal fats as a foodstvit? predominated, but the 

 unprecedented demand for them :or the use of millions of 

 armed men reduced the possibility of an adequate supply for 

 tho.se who remained at home. .Vs a correspondent of The 



Times Trade Su/>p/e»ie/i/, March 1918, points out, efficient 

 substitutes have been found in vegetable fats, chiefly derived 

 from the coco-nut and oil palms growing in profusi'm in the 

 tropical colonies of Great Britain and her allies. Vegetable 

 oil-palm growing is therefore of paramount importance, for 

 vegetable fat is a cheaper and more prolific production than 

 animal fat. 



The fact may be remembered that Germany firs 

 embarked upon a vegetable butter industry, which before the 

 outbreak of the war assuiped such, large proportions that 

 fleets of British ships were busily engaged in transporting 

 the raw material for vegetable oil from British and French 

 colonies to Hamburg. 



There has been a great deal of misconception in some 

 quarters about coco-nut or oilpalm growing in the tropics. 

 It has been thought that it does not pay, or that it takes too 

 long to reap returns. Modern methods of cultivation have- 

 however shown the fallacy of such ideas. 



By merely pursuing the policy of careful seed selection 

 for instance, it has been proved that a modern plantation can 

 be made to yield four or five times as much as by the old 

 'laissez faire' methods. It has also been pointed out that it 

 would pay handsomely t<> raise cattle and hogs on these palm 

 plantations, for the residue pulp from the nuts is a most 

 valuable feeding stuff. On the other hand, the animals 

 ensure an ample supply of manure for the trees, and thrive 

 on the sandy coast land under their shade. Until the palm 

 trees themselves attain an age at which they bear, the space 

 between the trees may be utilized for growing catch crops, 

 such as peanuts, which would materially lessen the cost of 

 the upkeep of the plantation until the palms begin to bear. 



Another profitable product of a coco-nut plantation is 

 coir or the husk fibre, the employment of which is now being 

 rapidly developed in the United States. Another apparently- 

 valuable byproduct from the coco-nut is the cellular refuse 

 which remains after the fibre has been extracted from the husk. 

 Experiments have shown that this po.ssesses high non-con- 

 ducting properties, equal in\this respect to cork dust, and it is 

 now being used in the manufacture of material for steam pipe 

 packing, and for the lining of refrigerating chambers. This 

 coco-nut husk dust has the great advantage over cork of being 

 much cheaper, and of being available in much larger tiuantities. 

 This new insulating material is called 'pectine'. 



The correspondent of T/te Times calculates that, whereas 

 in the temperate zone it requires 4 acies of fairly decent land 

 to support one cow or steer, on a palm estate in the tropics 

 no less than two cows or five hogs could be raised on an 

 average per acre, and that therefore, a coco-nut ox oil-pahn 

 plantation ought to be, if conducted on scientific principles, 

 an exceedingly profitably undertaking. 



Coco-nut and oil palms are cuiifined to a belt approxi- 

 mately within IS degrees of latitude north and south of 

 the equator. The cultivation of these palms m-:vy be enor- 

 mously extended. It is probable, for instance, that at least 

 50,000,000 more palm trees could be grown on the east coast 

 of Africa and in Madagascar. But possibly the most 

 favourable land for increasing the cultivation of vegetable oil 

 palms is the stretch of about (iOO miles on the north-east 

 coast of Brazil, where the nucleus of such cultivation now 

 exists of nearly 2,000,000 coco-nut trees, and about I -^0,000 oil 

 palms (E/atis iii'i'i'in^i*), which were orginally brought from 

 the Gulf of Guinea in slave ships. Strange to say, they 

 thrive better iu Bra'i! than in their original home, yielding; 

 a larger fruit with j iiieater percentage of oil- 



