326 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



cies, have much larger corpuscles than the perennibranchiate 

 Sii^edon. 



6. The corpuscles are not so large in Sleholdia^ which is 

 the largest sj^ecies, as in Amphiuma and Proteus, which are 

 much smaller species ; and so, too, of Triton and JLissotriton. 



The conclusion of Rudolph Wagner, that the largest size 

 of blood corpuscles related to the persistency of the gills in 

 the salamandroids, is not borne out by the observations of 

 Mr. Gulliver. He finds they are largest in Cryptohranclms 

 and A77iphm7naj hoth. of which have gills only when young, 

 losing them at an early age. aSTeither is there any relation 

 between the size of the species and the size of the corpuscles, 

 since these are larger in the little Proteus and A7np>hiuma than 

 in the gigantic Sieboldia. Although Mr. Gulliver has previ- 

 ously shown the existence of such a relation in one and the 

 same order of mammalia and birds, the rule does not apply 

 to the group of vertebrates just referred to. 11 A, 1873, 163. 



ABSOLUTE AMOUNT OF BLOOD IX ANIMALS. 



An investigation has lately been made by Steinberg in 

 reference to the absolute amount of blood in various animals, 

 as the result of which we learn that the relative weio-ht to 

 that of the entire body in the rabbit is as one in twelve to 

 thirteen ; in the guinea pig, one to thirteen ; in dogs, one to 

 eleven ; in puppies, one in sixteen to seventeen ; in cats, one 

 in ten to eleven; and in kittens, one in seventeen to eight- 

 een ; showing a much less percentage in the young of cats 

 and dogs than in adults. 21 A, June, 1873, 646. 



ox COLOR BLINDNESS. 



Professor Dor describes various experiments to settle the 

 question as to the nature of color blindness. The method 

 that he uses most frequently is that of viewing spectral colors 

 with a polarization prism. Dor rejects the theory of Young 

 and Helmholtz, that supposes three elements in the retina, 

 namely, those that respectively perceive red, green, and violet 

 or blue colors. He objects to this view on the ground both 

 of absence of anatomical proof, and, again, because of the 

 distinct vision of many of those who are afflicted with color 

 blindness ; and, again, because the spectrum, as observed by 

 two persons that came under his notice who had no percep- 



