104 CIRCULATING FLUIDS: 



diameter in the pigeon, duck, and goose, varies from -0008 to 

 •00044; the short diameter from -0004 to -00029. Wagner 

 estimates the two diameters, in the pigeon, at "0008 and "00033 

 respectively. 



"We find the largest blood- corpuscles in fishes. According 

 to Wagner ^ the largest corpuscles, at present observed, are 

 those of the torpedo, their long diameter being '002 ; in the 

 skate he found them to vary from -001 to -0012 in length; in 

 the loach the long diameter was '0005 ; in the eel-pout, 

 •00057 ; in the barbel -00066, the short diameter in this case 

 being -0004. 



In the carp the long diameter is -0005, and the nucleus 

 measures -00012. 



In the plaice, Schultz estimated the long and short diameters 

 at -00062, and -00043 respectively, and the thickness at -00007. 



In the naked amphibia the corpuscles are very large. In 

 the triton, Dumas and Prevost estimated the diameters at 

 •00128 and -00078 respectively. In the Salamandra cristata, 

 Schultz found that the diameters were -00138 and -000804 

 and that the thickness was •OOOSIS. In the frog, the same 

 observer estimated the length, breadth, and thickness at '00108, 

 and -00058, and -000017. 



Of all the amphibia, the water-snakes appear to possess the 

 smallest blood-corpuscles. 2 



The instantaneous effect of water upon the blood-corpuscles 

 is very remarkable, and is easily seen under the microscope : 

 they swell, become globular, lose their distinct contour, and (if 

 much water be added,) altogether disappear. If however the 

 blood-corpuscles have nuclei of sufficient magnitude to admit 

 of examination (as in the blood of fishes, reptiles, &c.), these 

 nuclei will be seen swimming in the water after the disappear- 

 ance of the capsules. 



The nuclei may be separated in a similar manner, by the 

 addition of a little acetic acid. The acid in a few minutes 

 dissolves the hamato-globulin, and assumes a yellow colour. 



' Zur vergleicheuden Physiologie des Blutes, 1833, p. 14. [The largest blood- 

 corpuscles do not occur in fishes, as stated in the text, but in some of the naked am- 

 phibia. See Wagner's Physiology, p. 236, English edition.] 



' A very complete account of the sizes of the blood-corpuscles of different animals, 

 as far as they had been then ascertained, may be found in Wagner's Nachtriige zur 

 Physiologie des Blutes, 1839, p. 31. 



