POPULAR MISCELLANY. 



251 



its course, the leaf follows, but the reason 

 is always a diminished tension on the illu- 

 minated side. This is true of the stalk as 

 well as of the flower. Hence the two phe- 

 nomena of periodic movement and of helio- 

 tropism depend on variations in the quantity 

 of the glucose contained in the point of 

 movement. 



Value of the Robin to the Agriculturist. 



— Like the English sparrow, the " robin " 

 {Turdiis migratorius) has human enemies 

 and detractors who will not admit that he is 

 of any use whatever to the gardener and 

 fruit-grower ; but assert that he prefers to 

 grow fat on stolen cherries and other small 

 fruits, rather than on an insect-diet. But 

 what are the facts ? Lieut. D. A. Lyle, U. S. 

 A., reared a robin from the fledgling state to 

 maturity, in the mean time closely studying 

 the bird's preferences in the matter of food, 

 and here is the result of his observations, as 

 communicated to the American Naturalist : 

 On being taken from the nest, the young 

 bird was placed in a cage, with plenty of 

 boiled eggs and mashed potatoes and pure 

 water. He would neither eat nor drink, but 

 sat drawn up in the bottom of the cage, 

 giving vent to an occasional chirp. The food 

 was then forced down his throat, and this 

 treatment revived the patient somewhat, 

 but did not give entire satisfaction. He 

 then received raw beefsteak three times a 

 day, with bread and egg at intervals. The 

 effect was striking: the eyes brightened, 

 the chirp became loud and strong, and the 

 bird would hop about briskly. He soon 

 learned to open his mouth for the food. 

 Next he was for three days restricted to a 

 diet of earthworms, of which he would eat 

 his fill, and then retire moodily to a corner, 

 there to remain for about fifteen minutes, 

 till the meal was digested. But, as this 

 food acted as a purgative, it was alter- 

 nated with beefsteak. The June beetle be- 

 ing then in season, that species of food was 

 tried, and the bird preferred it to anything 

 else. As long as June beetles could be pro- 

 cured, they constituted the sole food of the 

 bird, and he thrived marvelously on it. 

 Every day he consumed forty to fifty of these 

 large beetles. " One morning," writes Lieut. 

 Lyle, " at seven o'clock I gave him fifteen ; 

 I returned from the office at twelve, and from 



that time until sunset I fed him all he could 

 eat. During this time he disposed of seventy- 

 two of the large beetles ! " When the June 

 bugs were no longer to be had, cherries 

 were given to the bird. These, when he was 

 hungry, he would eat greedily, but they were 

 speedily rejected when a few coleoptera or a 

 piece of raw steak appeared in sight. The 

 author then makes an estimate of the num- 

 ber of insects probably destroyed per diem 

 by the twenty-three pairs of robins occupy- 

 ing the grounds around his residence, taking 

 as the basis of his calculation the perform- 

 ance of his captive robin, and finds that the 

 number would be at least 4,600, or 138,000 

 per month ! Examination of the cherry-trees 

 growing on the grounds showed that only 

 about one cherry in twenty had been injured 

 by the birds — a very low price to pay for 

 their service in exterminating the noxious 

 insects. 



Gelatine as a Food - Preservative. — Dr. 



Campbell Morfit's "gelatine process" for 

 preseiving articles of food — as milk, vege- 

 tables, fruits, etc. — possesses many advan- 

 tages which will undoubtedly win for it 

 a very general acceptance. It consists in 

 adding to the substances to be preserved a 

 certain proportion of gelatine, and then dry- 

 ing the mixture till it does not contain over 

 10 or 12 per cent, of moisture. The mode 

 of applying the process to the preservation 

 of milk is described as follows in Nature: 

 One pound of gelatine is dissolved in a gallon 

 of milk at a temperature of 130° to 140° 

 Fahr., and the solution is then allowed to set 

 into a jelly, which is cut into slices and dried. 

 By employing the product of this first opera- 

 tion in place of fresh gelatine for gelatinizing 

 a second gallon of milk, a jelly is obtained 

 in which the milk solids are just doubled in 

 amount. As a gallon of milk contains about 

 6,400 grains of these solid matters, viz., 

 casein, milk-sugar, milk-fat, and phosphates, 

 their ratio to the gelatine will become as 

 12,800 to 7,000 after the second operation 

 just described. If, then, the dried milk 

 jujube, as it may be now called, be again 

 and again employed with successive quanti- 

 ties of milk, a limit is reached when the one 

 pound of gelatine has been incorporated with 

 ten gallons. At this stage the mixture will 

 contain no more than one part of gelatine 



