The Development of a Leucocytozoon of Guinea-Pigs. 67 



appears to be due to a progressive increase in the activity of the alveolar 

 epithelium in secreting oxygen inwards. On raising the alveolar oxygen 

 pressure to normal, the difference between alveolar and arterial oxygen 

 pressure diminished rapidly. 



(13) Acclimatisation to high altitudes is due mainly to the increased 

 secretory activity of the alveolar epithelium, but partly also to the increased 

 lung ventilation, and to a lesser extent to the increased haemoglobin per- 

 centage in the blood. The acclimatisation takes some days to develop. 

 During rapid ascents in balloons or aeroplanes it would not have time to 

 develop, and this explains the contrast between the experience of 

 balloonists, etc., and that of mountaineers who ascend gradually. 



The Development of a Leucocytozoon of Guinea-Pigs. 

 By Edward Hal-ford Eoss, M.E.C.S. England, L.E.C.P. London. 



(Communicated by Sir Eonald Ross, K.C.B., F.E.S. Received January 23, — 

 Read February 29, 1912.) 



(From the Laboratories of the McFadden Eesearch Fund, Lister Institute.) 



[Plate 1.] 



The presence of " bodies " within the large mononuclear leucocytes of 

 guinea-pigs was first noticed by Kurloff (1898). He described them as 

 inclusions ; for in a drop of guinea-pig's blood he noted that many of the 

 large lymphocytes contained, within their cytoplasm, clear, spherical 

 vacuoles which were distinct from the nucleus, and which had not been 

 described before ; and he suggested the possibility of these bodies being 

 accessory nuclei. Since their discovery by Kurloff they have been sub- 

 jected to much research ; and papers describing various observations 

 concerning them have been published by Burnett (1904), Staubli (1905), 

 Goldhorn (1905), Ledingham (1906), Howard (1907), Pappenheim (1908), 

 Patella (1908), Hunter (1909), and Schilling (1911). 



Kurloff noticed that when the blood containing these bodies was fixed 

 and stained, they contained a nucleus-like structure staining with nuclear 

 ■dyes, but he believed them to be vacuoles formed by a secretion product of 

 the cells which held them. Ehrlich (1906) also thought that Kurloff s bodies 

 represented some " Secretstoff." Dr. Ledingham, to whom I am indebted 



f 2 



