322 THE BLOOD. 



what richer in haemoglobin than blood from fat ones of the same age. 

 The addition of iron salts to the food greatly influences the number of 

 blood-corpuscles and especially the amount of haemoglobin they contain. 

 The action of the iron salts is obscure. 1 There does not seem to be 

 any doubt that the iron contained in the food in the form of organic com- 

 pounds is active, but also iron salts and therapeutic iron. According 

 to BUNGE and his pupils the iron preparations act indirectly only. They 

 may combine with the sulphuretted hydrogen of the intestinal canal and 

 thereby prevent the iron associated in the food as assimilable protein 

 compounds from being eliminated as iron sulphide (BUNGE), a view which 

 is now generally discarded? 



An increase in the number of red corpuscles, a true " plethora poly- 

 cythcemia," takes place after transfusion of blood of the same species 

 of animal. According to the observations of PANUM and WORM MiJLLER, 2 

 the blood-liquid is quickly eliminated and transformed in this case 

 the water being eliminated principally by the kidneys and the protein 

 burned into urea, etc. while the blood -corpuscles are preserved longer 

 and cause a " polycythcemia." A relative increase in the number of red 

 corpuscles is found after abundant transudation from the blood, as in 

 cholera arid heart-failure with considerable congestion. An increase in 

 the number of red blood-corpuscles has also been observed under the 

 influence of diminished pressure or in high altitudes. VIAULT first called 

 attention to the fact that the number of red corpuscles was very great 

 in the blood of man and animals living in high regions. According to 

 him the llama has about 16 million blood-corpuscles per cubic millimeter. 

 By observations on himself and others, as well as on animals, VIAULT 

 found the first effect of sojourning in high altitudes was a very consider- 

 able increase in the number of red corpuscles, in his own case 5-8 millions. 

 A similar increase of the red blood-corpuscles, as also an increase in the 

 quantity of haemoglobin under the influence of diminished pressure, 

 has been observed by many other investigators in human beings as well 

 as in animals. Investigators are not united as to how this increase is 

 brought about. The increase in the blood-corpuscles is not absolute, 

 but is only relative, and it is considered by several observers that there 

 is neither a new formation nor a diminished destruction of the blood- 

 corpuscles. A relative increase may be brought about in different ways. 

 For example, another division of the blood-corpuscles in the vascular 

 system has been supposed, whereby the blood-corpuscles accumulate 



1 See Bunge, Zeitsehr. f. physiol. Chem., 9; Hausermann, ibid., 23, where the works 

 of Weltering, Gaule, Hall, Hochhaus, and Quincke are cited (the same work contains 

 a table of the quantity of iron in various foods); Kunkel, Pfluger's Arch., 61; 

 Macallum. Journal of Physiol., 16; Abderhalden, Zeitsehr. f. Biologie, 39. 



2 Pan urn, Virchow's Arch., 29; Worm Miiller, 1. c. 



