1902-3.] Dr G. A. Gibson on Some Observations on Cyanosis. 393 
Some Observations on Cyanosis. By G. A. Gibson, M.D., 
D.Sc., F.It.C.P.Edin., Physician to the Royal Infirmary, 
Edinburgh. 
(Read December 15, 1902.) 
The one constant factor in the production of cyanosis is diminu- 
tion of oxygenation. This may be the result of respiratory 
affections which hinder the access of air or diminish the area of 
the aerating surface, or it may, on the other hand, be due to 
circulatory disorders lessening the amount of the blood flowing to 
the lungs. These latter affections furnish the most conspicuous 
examples of cyanosis, and in them the symptom is entirely pro- 
duced by hindrance to the blood flow. Such is in reality the 
original conception advanced by Morgagni* and supported by 
numerous observers. The other view, apparently suggested by 
Corvisart, f that the condition is due to admixture of arterial and 
venous blood, is absolutely untenable, as in the vast majority of 
cases there is no possibility of such intermingling. In general 
terms the blood in cyanosis may be said to be of high specific 
gravity — from 1070 to 1080. The amount of haemoglobin rises 
considerably — often reaching above 100 per cent. The erythrocytes 
increase in number so as frequently to exceed 7,500,000 per cubic 
millimetre, while the leucocytes, although, not so commonly altered 
in number, often reach such a figure as 12,000 per cubic millimetre. 
The increase of these constituents of the blood was first observed by 
Toeniessen. I Malassez § showed that there are more red corpuscles 
in the blood of the superficial than of the deeper parts of the 
body. Toeniessen and Penzoldt || suggested that this might he due 
to loss of fluid from the surface, while the interior receives a con- 
stant supply of fluid from the alimentary tract. Eight years ago, 
* De Sedibus et Causis Morborum , tome 1, p. 154, 1761. 
f Maladies du Coeur , p. 281, 1806. 
X Ueber Blutkoryerchenzahlung bei Gesunden und Kranken Menschen, 
S. 29, 1881. 
§ Archives de Physiologic, ii. Serie, tome 1, p. 49, 1874. 
|| Berliner Klinische Wochensclirift, S. 45, 1881. 
PROC. ROY. SOC. EDIK — VOL. XXIV. 
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