292 Life and Letters of Francis Galton
When the individuals with a markedly hereditary taint were taken the resultant face had distinctly more delicate features, but the composite seems to the present wriaer too faint to provide much information ; further, these cases may well have shown on the average more emphasised emaciation. On the other hand, if a composite be formed of the far-advanced cases, where the emaciation is shown in the deeply sunken eye, the hollow cheeks, and thinly covered lower jaw, the face was not by any means of the narrow ovoid type. The authors do not state whether the chronic cases were more frequent in the hereditary and the rapid cases in the latter group. Possibly they might have gone further in compounding the material on the basis of the schedule data, but we must remember that the composite photographer has not only a temptation to compound the well-fitting faces, but that to do so is almost a mechanical necessity. As our authors put it
"We would also draw attention to the fact that this is the first attempt at applying the new process of composite portraiture on a large scale', and that many technical difficulties, mechanical and others, could only gradually be overcome." (p. 18).
Mahomed and Galton conclude finally that their results
"lend no countenance to the belief that any special type of face predominates among phthisical patients, nor to the generally entertained opinion that the narrow ovoid or 'tubercular' face is more common in phthisis than among other diseases. Whether it is more common than among
the rest of the healthy population we cannot at present say.
It is true that taking both sexes together we find 14.3 per cent. of faces that may be classed as ' narrow ovoids8,'and 9.3 per cent, that come under the head of ' broad faces with coarse features',' making in all 23.6 per cent, of our cases which may be grouped under one or other extreme departure in either direction from the normal average ; but we doubt if this is more than would be found among the general population. Our results are therefore negative, but it may be they are no less valuable; although we commenced our investigations with the expectation of establishing a 'type' on a firm foundation, we shall be little less satisfied with them if they have succeeded in refuting an error.
Although these conclusions would seem to indicate that there is no foundation for the belief that persons possessing certain physical characters are especially liable to tubercular disease, yet it may hereafter be proved that some explanation of the doctrine may be found in the course
of the disease when it attacks such persons." (p. 18.)
In the last paragraph our authors seem to have made an unallowable extension of their result. Were it true, we must totally deny the existence of any hereditary tendency to phthisis. Such, in my opinion, cannot be accepted in view of existing statistical data. Yet any hereditary tendency must depend upon a differentiation in physical structure, for that ultimately is what determines the efficient working of the various bodily organs. But it is idle in the present state of our knowledge to assume that there is a high correlation between the dynamical efficiency of the bodily organs and the physiognomy in particular. It is possible that nasal shape and carriage of the mouth might have some-probably not very ntense-correlation with a tubercular diathesis. But no special study of mouth and nose was
' When we note that composites of 50 to 200 components were made for the first time, we can appreciate the magnitude of the task.
2 What our authors term the 'tubercular' type.
' What they term the 'strumous' type.