1012 General Notes. [December, 



gives a color reaction with iodine, in five minutes. If the dias- 

 tatic power of the pig's pancreatic juice be represented by ioo, 

 those of the ox and sheep, feeders on matters poor in starch, are 

 respectively only eleven and twelve. Cold retards the action of 

 the pancreatic juice ; a temperature of from 30 to 45 C, is most 

 favorable to diastetic, while one of 6o° C. is most favorable to 

 proteolytic or tryptic action; and these actions cease to take 

 place at yo° C, and 8c° C, respectively. Double the quantity of an 

 enzyme will do its work in half the time, while half the quantity 

 will require double the time, but this rule of inverse proportion 

 is controlled by the rule that an enzyme liberates its energy at a 

 progressive!) retarded rate. 



The Birds of Heligoland.— The Bull. Soc. Z06I. de France 

 (1882) contains an interesting account of the birds of Heligoland, 

 by M. E. de Selys Longchamps. Herr Gatke, secretary of the 

 local government, is the resident ornithologist, and has collected 

 400 species out of the 500 known in Europe, including many 

 examples of some of the rarest species. In his own words, " Birds 

 from very different regions, from the north and south of Europe, 

 and all the north of Asia and America, choose this solitary rock 

 as a place of repose during their migrations." The island, a more 



little consistency that, at the rate it is wearing away, it will 

 disappear in four or five hundred years, lies in the direct course 

 of the birds which migrate every year from Southern Europe and 

 Africa to the Arctic regions. As many as 15,000 larks were 

 captured on the evening of Nov. 6, 1863. M. Gatke has proved, 

 by the concordant dates of the captures of erratic birds, that these 

 accidental migrations are regular up to a certain point, since for 

 the same species they take place at the same time of the year, 

 and in general consist of several species coming from the same 

 geographical regions. Among the birds taken are Phyllo^cnste 

 borcalis (Arctic Asia, X. E.America); PhvLnittdus (Himalayas); 

 Pllvl. coronatus (Malaysia); Calamodvt* ayicola (India— not 

 before observed in Europe); Cal. certhiola (coast of Sea of 

 Ochotsk); Pluvialis virginkus (Alaska); Totanus ni/cscens 

 (America), and Larus roseus, a circumpolar bird, lacking in most 

 collections. 



ZOOLOGICAL Notes.— The Quarterly Journal of Microscopical 

 Science for October, contains a brief account, by Dr. R. Horst, 

 with excellent figures, of the development of the European oyster. 

 He claims, contrary to Lacaze Duthiers and W. K. Brooks, that 

 the bivalve shell of Ostnea is originally unpaired, not devel- 

 oped from two separate halves, which afterwards unite and form 



a hinge. The thread cells and epidermis, with the lateral glands 



of Mvxine.the hag-fish have been studied by J. E. Blomfield.— — 

 The eye of Spondylus has been found by S. J. Hickson, to toe 



