308 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



lowing the cooler regions westward from Maine through the 

 Canadas and Red River region, thence northward nearly to 

 Sitka. From the latter point southward to Oregon both oc- 

 cur at the ordinary level, and rising as a more southern re- 

 gion is reached, until, at the latitude of Visalia, they occur 

 only a short distance below the snow line, at an altitude of 

 from ten to twelve thousand feet. 5 Z>, June^ 18V3, 360. 



DISCOVERY OF DANAIS ARCHIPPUS NEAR MELBOURNE. 



Professor M'Coy, of the University of Melbourne, announces 

 the discovery near Melbourne, in A23ril, 1872, of quite a large 

 number of specimens of an American butterfly, the Danais 

 archippus. He had previously received specimens from Lord 

 Howe's Island, on the northeast coast of Australia, and from 

 the Clarence River, in New South Wales ; and on the pres- 

 ent occasion they were detected at numerous points within 

 fourteen miles of each other. The fact is an extremely in- 

 teresting one, as there seems to be no reason to consider the 

 species as a permanent inhabitant of Australia, and it was 

 suggested that they may have been brought there by some 

 atmospheric current. 10 A, June^ 1873, 440. 



NUMBER OF THE RED BLOOD CORPUSCLES. 



By means of a simple apparatus, Malassez has succeeded in 

 counting the red corpuscles in the blood of several animals. A 

 known quantity of the blood is mixed with a preservative fluid, 

 and this is introduced into a flat capillary tube of known vol- 

 ume, and viewed under a microscope, the eye-piece of wliicli is 

 divided into squares. Knowing the number of corpuscles in 

 a square, the number of squares which include the tube, and 

 the volume of the tube, it is easy to calculate the number of 

 corpuscles in a cubic millimeter. (An ingenious microscopic 

 slide for this and many other similar purposes has been de- 

 vised by Mr. D. S. Holman, of Philadelphia, and is figured in 

 Nature for May 22, 1873, p. 79.) In mammals the number 

 of red corpuscles in each cubic millimeter varies from 3.5 to 

 18 millions. The average number in human blood is 4 mill- 

 ions; in that of camels, 10 to 10.4 millions; in that of goats, 

 18 millions; and in that of the porpoise, 3.6 millions. Birds 

 have fewer, the maximum being 4, the minimum 1, and tlie 

 mean 3 millions. Fishes have still fewer than birds, and 



