May 3, 1895.] 



SCIENCE. 



483 



appendix show tliat such an immunity may 

 either exist normally or be produced in cer- 

 tain mice, but that these cases are verj- ex- 

 ceptional, and it is very desirable that a 

 special research should be made to deter- 

 mine, if possible, the conditions upon ■which 

 such a continuance of immunity depends. 



8. An excessively high or low tempera- 

 ture has a decided eflect upon the produc- 

 tion of asphyxia by diminution of oxygen 

 and increase of carbonic acid. At high 

 temperatures the rcspiratorj' centers are 

 aifected when evapoi-ation from the skin 

 and mucous surfaces is checked bj- the air 

 being saturated with moisture ; at low tem- 

 peratures the consumption of oxygen in- 

 creases, and the demand for it becomes 

 more urgent. So far as the acute effects of 

 excessively foul air at high temperatures 

 are concerned, such, for example, as ap- 

 peared in the Black Hole of Calcutta, it is 

 probable that they are due to substantially 

 the same causes in man as in animals. 



9. The proportion of increase of carbonic 

 acid and of diminution of oxygen, which 

 has been found to exist in badly ventilated 

 churches, schools, theatres or barracks, is 

 not sufficiently great to satisfactorily ac- 

 count for the gi'cat discomfort which these 

 conditions produce in many persons ; and 

 there is no evidence to show that such an 

 amount of change in the normal proportion of 

 these gases has any influence on the increase 

 of disease and death rates which statistical 

 evidence has shown to exist among persons 

 living in crowded and unventilated rooms. 

 The report of the Commissioners appointed 

 to inquire into the regulations aft'ecting the 

 sanitary condition of the British Army, 

 properly lays great stress upon the fact that 

 in civilians at soldiers' ages in 24 large 

 towns the death rate per 1000 was 11.9, 

 while in the foot guards it was 29.4, and in 

 the infantry of the line 17.9 ; and shows 

 that this diflerence was mainly due to dis- 

 eases of the lungs occurring in soldiei-s in 



crowded and unventilated barracks. These 

 observations have since been repeatedly 

 confii-med by statistics derived from other 

 armies, from prisons, and from the death 

 rates of persons engaged in different occu- 

 pations, and in all cases tubercular disease 

 of the lungs and pneumonia are the dis- 

 eases which are most prevalent among 

 persons living and working in unventilated 

 rooms, unless such persons are of the Jew- 

 ish race. 



But consumption and pneumonia are 

 caused by specific bacteria, which, for the 

 most part, gain access to the air passages 

 liy adhering to particles of dust which are 

 inhaled, and it is probable that the greater 

 liability to these diseases of persons living 

 in crowded and unventilated rooms is, to a 

 large extent, due to the special liability of 

 such rooms to become infected with the 

 germs of these diseases. It is bj' no means 

 demonstrated as yet that the onlj- deleterious 

 effect which the air of crowded barracks or 

 tenement house rooms, or of foul courts and 

 narrow streets exerts upon the persons who 

 breathe it, is due to the greater number of 

 pathogenic microorganisms in such locali- 

 ties. It is possible that such impure atmos- 

 pheres may aftect the vitality and the 

 bactericidal powers of the cells and fluids of 

 the upper air passages with which they 

 come in contact, and may thus predispose 

 to infections the potential causes of which 

 are almost everywhere present, and espe- 

 cially in the upper air pas.sages and in the 

 alimentary canal of even the healthiest per- 

 sons; but of this we liave as j^et no scientific 

 evidence. It is very desirable that re- 

 seai-ches should I)e made on this point. 



10. The discomfort produced by crowded, 

 ill-ventilated rooms in persons not accus- 

 tomed to them is not due to the excess of 

 carbonic acid, nor to bacteria, nor, in most 

 cases, to dusts of any kind. The two great 

 causes of such discomfort, though not the 

 only ones, are excessive temperature and 



