322 PROCEED [NGS OF UNITED STATES NATIONAL MUSEUM. 



the above statement respecting the speedy death of surface swimmers is 

 the fact observed by myself, that a blue-fish {Pomatomns saltatrix (Linn.) 

 Gill) J taken August 5, showed distinct signs of life after fifteen minutes 

 spent upon the deck of the yacht, and that a fragment comprising rather 

 more than lialf the heart continued to x^ulsate for eight minutes after 

 being separated from the body, and to respond to artificial stimulus for 

 fifteen minutes longer. 



Prof. G. Brown Goode, of the Fish Commission, has been engaged for 

 some years in the investigation of the relations of our Atlantic fishes 

 to water temperatures. Last year (1878) he made several direct experi- 

 ments upon body temperatures, testing the temperature of the rectum 

 with a thermometer and comparing it with that of the water as indi- 

 cated by a deep-sea (Miller-Casella) thermometer. The experiments 

 were made upon cod and haddock for the most part, and the diiferences 

 between the rectum of the fish and the water from which it had been 

 taken were found to be inconsiderable, rarely exceeding one degree 

 Fahrenheit, as was the case in the similar experiments made by myself 

 last summer. In the cursory examination which I have made of the 

 literature of the subject I have found no other records of exact experi- 

 ments upon the animal heat of fishes. 



There seems to be, however, no lack of authority for the general belief 

 that these animals are cold-blooded, in the sense that they take on the tem- 

 perature of the medium which surrounds them, and have not, like the 

 higher vertebrates; a limited normal range of temperature, beyond wliich 

 life cannot be long sustained. Professor Owen lends the weight of his 

 great name to this opinion (in his general division of vertebrates into 

 Haematotherma and Haematocrya). and the instances which I now quote 

 of the endurance by fishes of extremes of heat and cold without apparent 

 injury are sufficient to establish incontestably the fact that they do possess 

 such endurance to a remarkable degree. The earlier citations are taken 

 at second-hand from Yarrell (Introduction to History of P>ritish Fishes). 



*Mr. Jesse {Gleanings in Natural History, 2d series, p. 277) tells of a 

 friend who saw a goldfish which had been frozen into a block of ice, 

 and afterwards thawed into life. 



* Dr. Richardson relates that the gray sncking carp, common in the 

 fur countries of Arctic America, may be frozen and thawed out again 

 without injury. {Fauna Boreali Americana, vol. 3.) 



* Perch ha\^e been frozen and transported for miles, returning to life 

 when thawed (T. S. Buchavan, Introduction to the Study of ^^ature)\ 

 and John Hunter says {Animal Economy) : " that these (fishes) after 

 being frozen still retain so much of life as when thawed to resume their 

 vital actions, is a fact so well attested that we are bound to believe it." 



tMr. J. W. Milner (Assistant Fish* Commissioner), had a mud minnow 



* Quoted by Yarroll, loc. cii. 



t Goode On the Migration of Fishes. Read before the American Fish Cultural Associa- 

 tion, February 28, 1878. 



J 



