roNSr.MI'TION 



439 



li-tiid- aii.l r. HIMI i if- is to be found rather in 

 the minimal amount of moisture present. Wet- 

 ness of tin- .soil is a factor of the greatest im- 

 portance, as was shown by the researches of 

 Bowdltch in America, Buchanan in England, and 

 Milroy in Scotland. Their united testimony was 

 thai the n 11 m KIT of cases of consumption varied 

 lireetly with the decree of dampness of the soil. 

 Klcvatum also exercises an important influence; 

 anil, other things l>eing equal, the more elevated 

 the district, the less favourable will it be to the 

 occurrence of consumption. The explanation of 

 tliis is probably to le found in the combined purity 

 ami rarity of the atmosphere. 



Tboogb consumption was early recognised as a 

 definite di-i-a-e, and its clinical course fairly well 

 xiiiilied, much obscurity has rested over the ques- 

 tion of its causation. About no disease has opinion 

 o persistently fluctuated. Definition was first 

 rigidly attempted by Bayle and Laennec, who held 

 that consumption was essentially due to the pres- 

 ence in the lung of little granular masses of varying 

 size and character, which were named Tubercle 

 <q.v.). On the other hand, Andral, Virchow, and 

 Niemeyer maintained that only a limited number 

 of cases were to be so explained, and that con- 

 sumption was most frequently induced by a process 

 of cnronic inflammation of the lung. This view 

 gave scientific basis to the popular belief in the 

 effects of neglected cold. Medical opinion was 

 divided between those main lines until 1882, when 

 Koch announced the fact that he had discovered 

 an organism, which he believed to be present in all 

 cases .of consumption proper. This organism the 

 Bacillus tuberculosis is a minute rod-like struc- 

 ture, capable of cultivation outside the human 

 body, and easy of demonstration in the expectora- 

 tion of consumptive patients (see BACTERIA). 

 Clinical and experimental evidence has since corro- 

 borated the truth of Koch's assertions, and the 

 bacillar origin of consumption has been pretty 

 .generally accepted, so that the older teaching has 

 been subjected to much modification. Although 

 this is so, considerable difference of opinion remains 

 as to the relation of other factors to the bacillus. 

 Some observers are even yet inclined to think that 

 certain cases of consumption may be satisfactorily 

 explained apart from the bacillus. This view is 

 very questionable. 



As regards the lung itself, the resultant condition 

 is more or less uniform, varying in degree accord- 

 ing to the stage of the disease. The process is one 

 of gradual disintegration, in which two phases may 

 be recognised : ( 1 ) Consolidation, when the affected 

 lung feels relatively solid, and the normal vesicular 

 structure can be but imperfectly distinguished ; 

 <2) excavation, when the consolidated mass in 

 part breaks down, leaving irregular spaces, varying 

 in si/.e, presenting an uneven, secreting surface. 

 The cavities ( vomicje) tend to l>e largest towards 

 the upper part of the lung. Associated with these 

 changes in the lungs, grave disturbance appears in 

 other organs, notably in the stomach and intestines, 

 the liver, and the kidneys. 



While accepting the bacillar origin of consump- 

 tion, it is impossible to overlook the predisposing 

 influence exerted by certain conditions. The list 

 of such factors is a large one. Pre-eminent among 

 them is Heredity (q.v.). Undoubtedly there exists 

 in many families a tendency to weakness i.e. a 

 less power of resistance of the respiratory organs. 

 This may l>e transmitted through several genera- 

 tions. This want of vital balance in the respiratory 

 apparatus is manifested by recurring 'colds,' with- 

 out apparently sufficient cause. It is not difficult 

 to realise how the bacilli take root, and flourish 

 more readily under such conditions. It is a Dia- 

 thesis (q.v.) or disposition which is inherited, 



rather than the disease. Greater difficulty in ex- 

 perienced when the question of actual traiiMiii*Mon 

 of the disease is considered. Though certain facto, 

 indeed, point to the conclusion, it cannot be -aid 

 that a congenital infection of child by mother ha* 

 yet been demonstrated in man. The so-called 

 scrofulous diathesis, in which there i.- a tendency 

 to a low form of glandular inflammation and 

 degeneration, has been cited in favour of this view. 

 The inter-dependence of scrofula and consumption 

 cannot be denied. Sex seems to have little liearing 

 in reference to consumption. Similarly of little 

 value is the popular belief that the disease is more 

 frequent in the offspring of consanguineous mar- 

 riages. It is, however, to be borne in mind that such 

 unions necessarily double the chance of a particular 

 family taint being reproduced. Age is a factor of 

 greater moment. It may be said that consumption 

 makes its appearance most frequently between the 

 ages of fifteen and thirty. It frequently attacks 

 persons beyond thirty, but in very young children 

 it is not common. A most important part in the 

 causation of consumption is undoubtedly played by 

 improper sanitary conditions. This is evidenced 

 by the much greater prevalence of consumption in 

 towns and other crowded centres. The statistics 

 of mortality in England illustrate this. In the 

 counties whose industry is chiefly agricultural, the 

 death-rate from consumption is comparatively low, 

 while in Lancashire and other more largely maim - 

 facturing counties the rate is high. Badly built, 

 overcrowded dwellings and workshops, with in- 

 sufficient ventilation and damp, afford the most 

 suitable conditions for the development of consump- 

 tion. All physicians are agreed that ' perhaps no 

 cause exerts such a decided influence on the pro- 

 duction of consumption as the privation of fresh 

 air and exercise.' No better illustration of this 

 can be cited than the excessive mortality from 

 consumption which was at one time recorded in 

 British and foreign prisons. Thus at Millbank 

 Penitentiary, during the seventeen years from 1825 

 to 1842, the annual mortality from consumption 

 was reckoned at 13 per 1000. The vicious influence 

 of these factors is, of course, increased enormously 

 when, in addition, poverty and want are present. 

 It must be admitted, too, that sedentary occupa- 

 tions generally predispose to consumption. Thus 

 tailors, seamstresses, and similar workers are 

 especially prone to the disease. More especially 

 is this true of occupations whose performance 

 necessitates the inhalation of dust particles e.g. 

 stone-masonry, knife-grinding, metal-polishing, 

 wood-carving, &c. The dust particles act as 

 irritants of the fine structures which line the air 

 passages and vesicles, inducing chronic changes, 

 which, in turn, are liable to lead to consumption. 



The bacillar doctrine has given fresh impetus and 

 scope to the important inquiry as to the contagious- 

 ness of consumption. On this subject the evidence 

 is conflicting. The large experience of consump- 

 tion hospital physicians, such as that of the Drs 

 Williams at Brompton Hospital, points decidedly 

 towards the negative view. On the other hand, 

 the statements of most careful observers, who have 

 again and again recorded cases of infection, are 

 strong in the opposite direction. An unprejudiced 

 review of the facts seems to justify the conclusion 

 that, although consumption is a communicable 

 disease, it is so within certain limits Le. 

 the contact and intercourse which, apart from 

 other causes, expose to risk, must be of an ex- 

 tremely close nature. Probably the expectoration 

 of phthisical patients affords the best means of 

 transmission. 



There remains the interesting question, whence 

 do the bacilli make their appearance? This is a 

 difficult problem. The fact that the organs of 



