328 THE TREND OF THE RACE 
fortuitous circumstance, there is doubtless a certain correlation 
between the kind of employment followed and inborn quality. 
As a result of the nature and diversity of industry, human beings 
are forced into lines of activity which very materially shorten life 
or cause a high percentage of accidental deaths. The differential 
death rate associated with various occupations is therefore a 
matter affecting the character of our racial inheritance. 
The racial effects of occupational mortality vary greatly from 
industry to industry. In many cases the result is doubtless 
dysgenic. Dangerous trades which draw workmen of skill and 
capacity are racially bad. The high mortality among locomotive 
firemen, iron workers, glass blowers, workers in porcelain, lead 
and copper represents a loss of an inheritance of at least good 
average quality. Occupations which draw and exterminate the 
more incompetent types may on the other hand be regarded as a 
racial benefit. 
Statistics on the average expectation of life of the followers of 
different trades and professions cannot always be accepted as an 
index of the relative healthfulness of the occupation in question. 
Those pursuits which are entered upon relatively late in life, such 
as the learned professions, tend to show an increased expectation 
of life because cases of death before the professional career is 
begun are not included. The average duration of life among 
casual laborers is decreased by the occurrence of many deaths in 
the ages below 20 years, but this would not be the case among 
clergymen or physicians. An index of occupational mortality 
which is better than the average age of death is afforded by the 
mortality at various ages of life. 
The actual death rate among the followers of any occupation 
is a result of two sets of factors: (1) Those concerned with the 
occupation itself, and (2) those depending upon the kind of 
human material the occupation selects. Of the first, the whole- 
someness of the occupation itself is of prime importance. Many 
trades cause a slow poisoning of those engaged in them. The 
disastrous results that follow work in lead industries have already 
been commented on. Phosphorus poisoning is not uncommon 
