322 Proceedings of the Koyal Society of Edinburgh. [Sess. 
associated with relative lymphocytosis mentioned in Gulland and Goodall 
(. loc . cit., p. 79), only one, chronic catarrh of the small intestine, seems to 
have any relation to the condition met with in gas poisoning. Undoubtedly 
gastric catarrh is a prominent symptom in a large proportion of these cases. 
Another pathological condition, in which the lymphocytosis is not 
merely relative but absolute , is whooping-cough. This is, of course, a 
subacute condition of the larger bronchial tubes, believed to be due to a 
specific organism, the bacillus of Bordet and Gengou. This disease presents 
a very close analogy to the cases of gassing, in which the respiratory tract 
is mainly affected. 
The blood change would appear to have no relation to the nature of 
the gas employed. Apparently, therefore, it is due to some change set up 
which is common to all types of gas poisoning. It may be that it is the 
chronic catarrh of the respiratory or alimentary mucous membrane which 
explains it, but we are still in the early stages of our knowledge of the 
effects of gas poisoning on the body. They are undoubtedly very profound 
and persistent. So far as we have been able to ascertain, no mention is 
made of a blood change, such as we have observed in any official study of 
cases of gas poisoning, or in experimental records published by physiological 
investigators. We know, however, that catarrh of the respiratory and 
gastric mucous membranes is present in the early stages, and tends to 
persist. Lymphocytosis is met with in tuberculosis, syphilis, whooping- 
cough, and gastro-intestinal catarrh, and other subacute and chronic 
infections. From analogy, therefore, one would judge that chronic catarrh 
is the main factor in the production of the change. We are at present 
extending our observations to other chronic inflammatory diseases of the 
lungs and mucous surfaces, and we hope on a subsequent occasion to be 
able to present further statistics with reference to the occurrence of 
lymphocytosis in these diseases. 
Summary. 
1. In cases of gas poisoning in * which symptoms persist there is an 
increase in the number of lymphocytes, relative and absolute, in the 
circulating blood. In slight cases this may not be beyond the normal 
limits, or in excess of what may be met with from other causes. In any 
marked case, however, the change is sufficiently striking to be of some 
importance in cases where the medical officer is in doubt as to the reliance 
to be placed upon the statements of men complaining of having been 
gassed. 
2. The blood change is elicited by a differential count of the leucocytes, 
