SCIENTIFIC NEW^S. 



[May I a, 1888. 



into execution on the large scale by the British Fish 

 Culture Society, whose prospectus is now before us. 



The most prominent feature in the new process is the 

 substitution of a natural food, for the chopped liver which 

 has been hitherto supplied. This natural food consists of 

 minute living animalculas, such as Entomostraca, Vorti- 

 cellse, etc. These little creatures multiply in water with 

 singular rapidity, and Mr. Paul has devised a method of 

 breeding them so readily that food for any conceivable 

 quantity of fish can be obtained with very little trouble 

 or expense. 



The advantages of this animalcular food as compared 

 with liver are that it is much more completely digested 

 and assimilated. Of the liver nearly three-fourths are ex- 

 creted by the fish without being utilised. Bits of liver 

 too escape uneaten, and hence much trouble is thrown 

 upon the keepers, since, if such impurities are not re- 

 moved, they putrify and cause the fish to perish. It 

 has been found in actual practice that trout and salmon 

 fed upon this natural food grow three times more 

 rapidly than such as are reared upon boiled liver, whilst 

 their flesh is more wholesome and more palatable. 



A second improvement which Mr. Paul proposes is 

 that the fish, instead of being passed at once from the 

 breeding-boxes to the rivers, are kept in graduated ponds 

 and tanks, where they can be protected from many of their 

 enemies, and where they can receive a regular supply 

 of food. By these arrangements it is rendered possible 

 to rear 900 out of every thousand ova laid by a trout 

 or salmon, instead of one (!) as is the natural average. 



A further step in the right direction is Mr. Paul's 

 method of fattening fish. We are informed that fishes 

 measuring only 6 in. have been brought in twelve 

 months to a length of 20 in. and a weight of 12 lbs. on 

 his system. 



If this process succeeds — and succeed it must, from 



the facts already ascertained, if it only meets with 

 fair play — ^several beneficial results must follow ; such, 



for instance, as an increased supply of human food at 



non-prohibitive prices. 

 Of course we are aware of the contempt in which 



" coarse fish " — i. e., any fresh-water fish save trout and 



salmon — is held in England. But the fault lies not in 



the fish, but in the methods of cooking. 



That this Society has our best wishes scarcely need 



be said. 



The Growth of Plants. — According to the Annales 

 Forestieres a person not named, at Avignon, has been 

 repeating the celebrated experiment of Helmont. He 

 took ICO kilos, of soil, dried it in a stove and put it in a 

 stoneware pot. The soil was then moistened with rain- 

 water, and a willow was planted in it weighing 2! kilos. 

 For five years the soil was carefully moistened with rain 

 or with other water. The willow grew and increased ad- 

 mirably. In order to prevent the introduction into the pot 

 of other earth or of dust, it was covered with a metal plate 

 perforated with a great number of fine holes, so arranged 

 as to give access to air only. (If air can find access dust 

 will certainly not be excluded). At the end of five years 

 the tree was pulled up, and its weight was found to be 

 about 85 kilos., not including the weight of the leaves 

 which had fallen off every season. When the earth had 

 been dried it was weighed again, and was found to have 

 lost only 60 grammes. Therefore nearly 80 kilos, of 

 woody fibre, bark and roots had been produced. What 

 was their source ? In addition to the carbonic acid of 



the air which the Annales mentions, the ammonia of the 

 atmosphere and the mineral matter present iii the water 

 must be taken into account. The experimentalist does 

 not seem to have determined which part of the gross 

 weight of the tree was moisture. 



Struggle for Existence. — M. L. Speich writes in 

 Cosmos that the walls of a room in his house are hung 

 with a paper having a white ground covered with a 

 pattern of yellowish figures, terminating in points. 

 Entering this room, which was unoccupied, he noticed 

 that a number of these points seemed rather deeper 

 coloured than the rest. On close examination he found, 

 sitting on each, one of those little moths the despair of 

 housewives, placed with its head towards the point of 

 the design, whilst the margins of its wings coincided 

 exactly with its outline. Thus placed and flattened upon 

 the spot selected, these insects were almost invisible. 



A New Fossil Fish from the Coal Measures of 

 Commentry. — M. Charles Brongniart (Comptes Rcndus) 

 describes certain specimens from Commentry which form 

 the types of a new order, pleurocanthides, the ancestral 

 and synthetic group of the true sharks, the rays, the 

 Port Jackson sharks, the Chimaerac, the sturgeons, and the 

 Ceratodus. 



The Food of the Tawny Owl. — According to the 

 Newcastle Weekly Chronicle, there is at present on Derwent 

 side a nest of this species containing six young ones, a 

 very unusual number. On the nest there had been laid 

 out twenty-five full grown mice and six halves of mice, 

 includmg house-mice, field-mice, harvest-mice, and 

 dormice. Such a bill of fare ought to plead convincingly 

 for the protection of this useful bird. 



Influence of the Moon on Crustaceans. — Mr. E. L. 

 Layard, British Consul at Noumea, writes {Field) that a 

 certain crab found in the islands of the Western Pacific 

 is " full of splendid meat " if taken at full moon, but if 

 captured at new moon it is worthless, the flesh being 

 flaccid and watery, and the animal very much reduced in 

 weight. He seeks to account for this fact by suggesting 

 that at full moon the crabs can see better to capture their 

 prey. 



Exploration of Iceland. — During the coming sum- 

 mer — if one does come — the Danish Government 

 purposes despatching an expedition to Iceland to survey 

 the coasts and take soundings. 



Capture of Myrmekophilous Insects. — This name 

 has been given to certain beetles and other insects as 

 well as spiders and mites v;hich live in ant-hills, and from 

 some unknown reason are not devoured by the inhabi- 

 tants. Most of them are very rarely met with in other 

 localities. To capture such insects without having the 

 hands, arms, and probably the face covered with ants. 

 Dr. W. Behrens proposes (Stettin Entom. Zeitschrift and 

 Humboldt) the following method : — The lid of a common 

 paper box is perforated with holes of about | inch in 

 diameter. A bit of cheese is put in the box, the lid put 

 on, a cord of about a foot or 18 inches in length is tied 

 to the box, which is then buried in the ant-hill. 



The next day the place is revisited, the box is quickly 

 drawn out by means of the cord, placed in a larger box 

 and carried home for examination. 



