1902-3.] Dr G. A. Gibson on Some Observations on Cyanosis. 395 
to raise that impelling the fluids into the commencement of the 
lymphatics, but it must not be forgotten that an elevation of pres- 
sure in the great veins will hinder the return of the lymph by 
pressing upon the openings of the lymph vessels into the veins. 
It is probable that the increase in the red corpuscles may be to 
some extent compensatory in cases of cyanosis. To say this, how- 
ever, is not enough ; it affords no rational explanation of the process 
by which the increase is brought about. Nature does not work by 
such direct methods as would require to be invoked if the increase 
of the corpuscles were regarded as a simple compensatory change, 
balancing the diminished power of oxygenation. Compensation in 
valvular lesions, for example, is produced by the definite structural 
changes constituting hypertrophy, caused by increase of work, and 
compensations in cyanosis must have some reasonable explanation 
also. It seems to me that such an explanation may be found in a 
consideration of the functions of the red corpuscles under changed 
conditions. In venous stasis the corpuscles are insufficiently 
oxygenated, they cannot perform such an active part as oxygen 
carriers, and they cannot yield so much oxygen to the tissues. It 
must further be remembered that in cyanosis there is less 
metabolism in the tissues, and therefore less waste produced. In 
a word, the functions of the corpuscles being lessened, the tear 
and wear which they undergo is reduced, and the duration of 
their individual existence increased. The number of the corpuscles 
must in this way be proportionately augmented, and this must lead 
to the numerical increase, as well as to the high percentage of 
haemoglobin, until a balance is struck between the production and 
the destruction of the blood- corpuscles.” 
In some subsequent remarks upon this subject * it was frankly 
stated that this explanation could only be seriously entertained if 
the increase in the blood elements was found to exist throughout 
the different divisions of the circulatory mechanism — arteries, 
capillaries, and veins — but that the observations of many workers 
on the state of the blood in high altitudes were strongly in support 
of it. 
The object of the present communication is two-fold : in the 
first place, to show what relationship exists between the conditions 
* Diseases of the Heart and Aorta , p. 211, 1898. 
