416 BLOOD AND LYMPH. 



tity of hemoglobin is estimated, the average figures obtained for 

 the animals at low levels are the same as for those at the high 

 altitudes. Zuntz has, however, called attention to the fact that 

 when Abderhalden's figures are estimated per kilogram of weight 

 they show an increase in total hemoglobin in the high altitudes, 

 and he and other observers have obtained similar results. It 

 seems certain, therefore, that high altitudes cause eventually a 

 marked increase in the production of red corpuscles, but that the 

 very sudden changes of this kind reported by some authors as 

 happening within a few hours must be considered as apparent 

 rather than real, and are to be explained by some change in the 

 water contents or in the distribution of the blood.* 



Physiology of the Blood Leucocytes. The function of the 

 blood leucocytes has been the subject of numerous investigations, 

 particularly in connection with the pathology of blood diseases. 

 Although many hypotheses have been made as the result of this 

 work, it cannot be said that we possess much positive information as 

 to the normal function of these cells in the body. It must be borne 

 in mind, in the first place, that the blood leucocytes are not all the 

 same histologically, and it may be that their functions are as diverse 

 as their morphology. Various classifications have been made, 

 based upon one or another difference in microscopical structure and 

 reaction, but at present the system most used is that adopted 

 by Ehrlich-t According to this nomenclature, the white cor- 

 puscles fall into two main groups, the lymphocytes and the 

 leucocytes, and each of these into two or more subgroups. Thus: 



I. LYMPHOCYTES. No granules in the cell substance, and, though capable of 

 ameboid changes of form, this property is not characteristic and prob- 

 ably not sufficient to cause locomotion. 



(a) Small lymphocytes are about the size of the red corpuscles; the nu- 

 cleus is large, symmetrically placed, stains homogeneously, and the 

 cytoplasm is reduced to a very small amount. They form from 20 

 to 25 per cent, of all the white corpuscles. 



(6) Large lymphocytes. Two to three times as large as the preceding. 

 Nucleus somewhat eccentric; the cytoplasm is relatively more 

 abundant than in a, but non-granular. These forms exist only in 

 small numbers, forming 1 per cent, or less of the white corpuscles. 

 II. LEUCOCYTES. Granules of different sorts found in the cytoplasm. Cells 

 characteristically ameboid. 



(a) Transition forms (uninuclear leucocytes). Single large nucleus, more 

 or less lobulated; cytoplasm abundant and faintly granulated. The 

 granules stain with neutral dyes and are therefore designated as 

 neutrophile granules. The name, transition form, implies that these 

 leucocytes represent an intermediate stage between the large lympho- 

 cytes and the following variety. This form exists in small numbers, 

 2 to 10 per cent, of the total number of white corpuscles. 



* For the extensive literature see Van Voornveld, "Das Blut im Hoch- 

 gebirge," "Pfliiger's Archiv," 92, 1, 1902; Zuntz et al., "Hohenklima und 

 Bergwanderungen in ihrer Wirkung auf den Menschen," 1906. 



t Ehrlich, "Die Anaemic," 1898; see also Seemann, "Ergebnisse der 

 Physiologic," 3, part i., 1904. 



