NO. 2$ INFLUENCE OF ATMOSPHERE OX HEALTH 39 



Sequard and D'Arsonval, it seems probable that the cases in which 

 the last animal in the series survived some of the others and a low 

 percentage of carbonic acid was found in the jar, should be attributed 

 entirely to defects either in methods of air-analysis or in the appara- 

 tus, or in both. If, however, the life of the last animal was ap- 

 parently saved by H 2 S0 4 , it was due to leakage in the connections 

 from the increased resistance caused by the interposition of the 

 absorption tube. This is an important fact, which is in direct oppo- 

 sition to the theory of 11 row n- Sequard and D'Arsonval with regard 

 to the influence of H 2 S0 4 in the absorption tubes." .... 



" In experiment No. 7,3, with a series of six rabbits confined for 

 two days, the proportion of carbonic acid in the last two jars, 

 for the greater part of the time, was between 4 and 7 per cent, and 

 that of the oxygen between 12 and 16 per cent. None of the animals 

 died or were seriously ill. Those in the first three and in the fifth 

 jars gained in weight, those in the fourth and sixth lost slightly in 

 weight." 



An experiment of this nature, and result, once and for all negatives 

 the organic poison theory. 



The experiments have shown that animals such as mice may live 

 in an atmosphere in which, by gradual change, the proportion of 

 oxygen has become so low and that of the carbonic acid so high that 

 a similar animal, brought from fresh air into it, dies almost immedi- 

 ately. This immunity may continue when the experiment is inter- 

 rupted for a day or two. The immunity is exceptional, is limited to 

 certain individuals, and requires further enquiry. 



We (M. F. and L. H.) repeated the Brown-Sequard experiment 

 and placed two chambers (capacity (> liters) in series, the one con- 

 taining three rats and the second a guinea-pig; in another series we 

 placed three rats in the first and three rats in the second chamber. 

 Air was aspirated through each series at such a rate as to give 2.5 

 to 4 per cent C0 2 in each of the second chambers. We cleaned out 

 the animals' chambers each day, and filled them with dry hay so as 

 to avoid the cooling and wetting effect of the air, which was 

 saturated with moisture. The experiment continued for three weeks 

 and both the guinea-pig and the rats in the second chamber in- 

 creased in weight. 



Finally, the first of these two experiments terminated by an 

 accidental failure in the aspirating current which led to the asphyxia- 

 tion of the animals in both chambers. 



