730 BLOOD in cases of suspected poisoning by them. It has been said that arsenic exists normally in blood, but this assertion has been disproved. Nickles has pointed out the existence of an in- teresting element in blood, fluorine. The blood of man differs from that of woman, as will be seen by the following comparative analyses made by Becquerel and Rodier : Density of defibrinated blood 1060-8 Water 779 Corpuscles 141-1 Albumen 69-4 Fibrine Extractive matters and free salts. . . Fattv matters Seroline Phosphorized fatty matter Cholesterine Animal soap M 6-8 1-600 0*20 0-488 0-OS8 1-004 1057-5 791 127-2 70-5 2-2 7-4 1-620 0-020 0-464 O'O'.IO 1-046 The same chemists have also found that there is less iron in the blood of woman than in that of man. The blood of children is richer in solid constituents, and especially blood corpuscles, than that of adults. It is just the reverse with the blood of old people compared to that of adults. During pregnancy the blood contains more water than in other circumstances ; the quantity of albumen and of blood corpuscles is diminished. Cazeaux has justly pointed out that the so-called plethora of pregnant women is not a plethora of blood, but of water, and that it is usually very wrong to bleed women during pregnancy only because they seem to have too much blood. Among animals, the blood of omnivora and carnivora is richer in organic solid constituents than that of the her- hivora. So also is that of the warm-blooded vertebrata, compared to the cold-blooded. The blood of the arteries differs from that of the veins in many points. Its corpuscles have a smaller quantity of solid constituents, especially fats, but they contain relatively more hasma- tine and salts. It has more fibrine and more water, and therefore relatively less albumen. It has also a much smaller quantity of fats, and a much greater amount of extractive matters, while its salts are diminished. For the com- position of the blood of the portal and hepatic veins, see LIVER. Changes in the composition of the blood are effected very quickly ; during digestion, for instance, the solid constituents of the blood manifestly increase, while the re- verse takes place during fasting. In all the circumstances which modify the blood, it is chiefly the number and the composition of the blood corpuscles which change. The differ- ences between different animals as to the quan- tity of blood corpuscles are very great ; for in- stance, the pig has 145-5 of dry blood corpus- cles, while the goat has only 86-0, out of 1,000 parts of blood. Of course this relates only to dried corpuscles, as Lehmann has found that the normal corpuscles in man form more than one half the quantity of the blood. When it is said that the proportion of corpuscles is only T^jf of the blood, this relates to dry cor- puscles. The proportion of this most important element in the blood of man is put down at a higher or lower amount, according to the means employed to separate or to dry them. In this way we may explain how Lehmann gives the proportion of 149-485 for the dry corpuscles in 1,000 parts of blood, while Bec- querel and Rodier give the proportion of 141-1, Richardson 134-8, Lecanu 132-5, Prevost and Dumas 129-0, Andral and Gavarret 127'0, Popp 120-0, Nasse 116-5, and Soberer only 112-0, for the blood of man. The quantity of fibrine in the blood, even in very weak anaemic or hy- drajmic persons, increases in all cases of inflam- mation accompanied with fever. IV. MICRO- SCOPICAL STCDY OF THE BLOOD. When the blood is examined with a microscope, many things may be found : 1, red corpuscles or disks ; 2, white, or rather colorless, corpuscles ; 3, molecular elements ; 4, pigment ; 5, crystals ; 6, coagulated fibrine. We will study succes- sively these different elements. 1. Bed corpus- cles or disks. Their discovery is due to Mal- pighi (in 1666), although it seems that Swam- merdam had seen them a few years before. They are found in the blood of all the verte- brata. Their form varies much in animals of different classes. In mnn they are thick, cir- cular, slightly biconcave disks, consisting of a colorless investing membrane, and of red or, in refracted light, yellow, viscid, fluid contents. They have no nucleus, at least in adult men. In the other mammalia the red corpuscles are more or less similar to those of man except, however, a few tribes (camel, dromedary, lla- ma), in which the red corpuscles are not circu- lar and concave, but elliptic and biconvex. In birds they are also elliptic or oval, and elevated in the centre. In ampliibia they are oval also, and strongly convex. We owe to the laborious researches of Gulliver the indication of the size of the red corpuscles in an immense number of animals. We will take from the table he has published only what relates to man and to the most common animals, or to those which have MEASUREMENTS OF THE RED CORPUSCLES OF THE BLOOD. MAMMALIA (continued). Long diameter. 28. Beaver SJi'25 24. Guinea pig 8588 I. MAMMALIA. Long diameter. 1. Man 8200 2. Monkeys, from 8624 to 8888 8. Bats, from 4465 to 4175 4. Mole 4747 5. Bear (Ursus Ameri- canus) 8698 6. Dog 8542 7. Wolf 3600 8. Cat 4404 9. Lion 4322 10. Tiger 4206 11. Whale 8099 12. Pig 4230 13. Elephant 2745 14. Horse 4600 15. Ass 4000 16. Ox 4267 17. Eeddeer 4824 IX. Sheep 5800 19. Goat 6866 20. Hare 8560 21. Kabbit 3607 22. Mouse ... . . 3614 II. BlEDS. 1. Raven ... . . 1961 2. Swallow 2170 8. Cock 2102 4. Swan Itn6 III. REPTILES. 1. Tortoise (land) 1252 2. Alligator 1824 8. Lizard 165B IV. AMPHIBIA. 1. Common frog 1108 2. Common toad 1043 8. Siren 420 V. FISHES. 1. Perch 2099 2. Carp 2142 3. Eel 1745
