ļ
The theory of Mathesis--the question as to whether the children of tuberculeus
perents suffer from a groster liability to tuberaulesis frem enhanced susceptibility
resulting from'paratubereulous lesions' due to toxie astien en the germ selli
the hereditary tranmission of eenstitutional predisposition to tubersulesis,is
being relegated mere and were to the realms of improbability as modam kneviedço,
with its insistese en rosuracy of detail,demands frota and proefs in plate of
nebulous hypotheses,
The dominating faster in the insidese of tuberculosis is the opportunity for
infection; in other words, the greater the opportunity for infestion the greater is
the incidence and the mortality from this disonas, Dan we argue that the reverse of
this also holds good,namely that a high incidence and mortality mean greater opper-
tunities for infestion ↑ Probably we can,as will be shem later when the local sen-
ditions are mentioned, Otherwise we are throw back again to the predisposition iden,
balking enquiry, darkening knowledge, and 'using the names of things instead of
things'; it has vertainly bean shem in some cities (New York, for example) that by
limiting the ppportunities for infestien the insideos of the disense is greatly
limited also.
It would appear to be establishes that under sertain cireumetanses,no matter what
the 'diathesis' may be,infection can always be effective. To prove that some shll-
dren inherit a predisposition to tuberculosis the insidmes of the diseḥse amongst
the offspring of tuberculeus parents and amenget equal numbers of non-tubersuleus
parents would have to be sexpared, and, furthermore, it would be essential that beth should be subjected to the same environment from birth,at HeFadycan has pointed out,
Even then we must bear in mind the fact that the former will have been expɑasi te
infection during the intra-uterine paried,se that the senditions for comparisen will not be strictly impartial. To compare, as has been dene, the death-rate from tubersul- esia arengat members of the twe ontogeries—the shildren of healthy parents on the
several
ans hand and these af tuberculous parente en the ether-is fraught with fallker, au
the after senditions are so diverso. To make them more aquable it would be necessary
for the children of healthy parents to be bem in infected houses or be placed there
at birth, slearly an impossible condition except by more resident,
The children of tubersulsus parents are thus handisapped in surźkus ways, sash of which plays a part in rendering fallacious the semparison of their death-rate with that among children of healthy parents; the chief of these disturbing fusters would be: 1.Intra-uterine exposure. 2.Birth in infested surroundings, and, therefore,greater liability de infection while young. 3.The dose of infecting material is likely to