SCIENCE- GOSSIP. 



355 



It is curious that horse-fat derived from any 

 part of the animal is soft and of about the con- 

 sistency of butter. Even that from the kidneys is 

 semi-fluid and quite different from the kidney fat 

 of the sheep, which is hard and tallow-like. 



The food of an animal appears to have a con- 

 siderable influence on the consistency and com- 

 position of its fat. It is well known that the fat 

 of American pigs is much more fluid and capable 

 of combining with more iodine than that of Euro- 

 pean pigs. This is possibly due to the presence of 

 a larger proportion of the more unsaturated linolic 

 acid derived from the oil in the maize on which 

 American pigs are frequently fed. 



The effect of captivity on the fat of wild animals 

 is shown in a series of interesting results obtained 

 by Amthor and Zink. 



The amount of liquid fatty acids (oleic, linolic 

 etc.), as measured by the proportion of iodine with 

 which they could combine, was found to be lower 

 in the fat of domestic animals than in that of the 

 corresponding wild animals, and the more fluid 

 character of the fat was also indicated by its 

 higher melting-point, as shown in the following- 

 table : — 



Per cent, of 

 Fat. Melting-point Iodine 



0. absorbed. 



Domestic Cat 39—40 .. 54.5 



WildCat 37—38 .. 57.8 



Tame Rabbit 40—42 . . 69.G 



Wild Rabbit 35—38 .. 99.8 



Goose 32—34 .. 67.G 



Wild Goose . . 99.G 



Wild Goose (2 years' captivity) .. .. 67.0 



Duck 36—39 .. 58.5 



Wild Duck . . 84.6 



In the case of birds, the fat of the domestic 

 goose, duck and hen resembled lard, whilst that 

 of the related wild birds was oily. 



The fat of the wild boar was found to differ from 



Fig. 4. Fat-cells, some showing Nucleus, 

 and one Fat-crystals. 



ordinary lard in possessing more liquid fatty acids, 

 and especially in having drying properties. 



This remarkable property of drying, which has 

 never been previously recorded of any animal fat, 

 was also possessed by the fat of the hare and wild 

 rabbit, and to a lesser extent by that of the black- 

 cock. 



The fat of the polecat was quite liquid, whilst 

 that of the dog and the cat resembled lard in 

 appearance and general characteristics. Fox-fat 

 was like that of dog, but more liquid. 



The fat of marine animals and of fishes has beei 

 less studied than that of land animals, and many 

 of the results which' have been published require 

 confirmation. 



Speaking generally, they are oils that contain 

 very unsaturated liquid fatty acids, and some 



Fig. 5. Apparatus for Determining Stearic Acid. 



of which resemble linseed-oil, though without 

 possessing its drying properties. 



I have to express my thanks to Messrs. Chas. 

 Griffin & Co. for permission to use the blocks, in 

 figs. 3 and 4, and to Dr. Sykes, editor of the 

 "Analyst," for the loan of the block of fig. 5. 



57 Chancery Lane, London. W.C. 



Algol. — Professor A. A. Nijland. of Utrecht, 

 finds that the light curve of this star during 

 decrease, is not so regular as is usually described, 

 but in reality shows a marked break. 



Flying Fish. — From time to time a question 

 interesting to naturalists is raised as to the mode 

 of flight of the " flying fish.'* Does it really fly as 

 do birds, or is its passage through the air simply a 

 blowing along by the wind in conjunction with 

 the impetus given by its leap from the water ? I 

 believe that close and constant observation would 

 prove that the pectoral fins of the fish do not 

 vibrate, and that they are incapable of flapping 

 as the wings of birds flap ; also that the fish does 

 not " fly " in calm weather. Further, that it 

 generally "flies" up the wind, and that the fact of 

 its rising above the waves in a forward movement 

 is due to the upward direction of the wind from 

 the waves. The flight of the fish resembles in 

 many particulars the soaring flight of oceanic 

 birds ; a rapid vibratory motion of the anal fins is 

 sometimes very noticeable. It would be interest- 

 ing to hear other opinions on this point, and I 

 should personally be much obliged for any informa- 

 tion or for photographs showing the fish in the act 

 of flight. — I). Wilson Burlier, (rreenJiithe. 



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