A Review: Osteopsathyrosis 
factors that inhibit the action of the 
normal ones. 
As students of heredity, therefore, 
Professor H. S. Conard, of Grinnell 
College, and Dr. Charles B. Davenport, 
of the Carnegie Institution, have re- 
viewed the literature on the subject, 
added some new cases, and published 
their conclusions in a bulletin? of the 
Eugenics Record Office. They accept 
the finding of Schwarz and Bass (1912) 
that heredity is the only important 
etiological factor in bringing about this 
condition, and are able to quote thirty- 
five family histories in support of it. 
As an example we notice the chart of 
four generations of a family found by 
Professor Conard: 
In the first generation are two 
affected brothers, one of whom had a 
thigh broken merely from the muscular 
strain on a turn while dancing. The 
other brother has a record of a broken 
thigh and dislocated hip. 
From the latter are eight children, 
half of whom showed the father’s 
abnormality. 
In the third generation the number of 
affected persons becomes still greater, 
although none of the second generation 
children had married mates with similar 
petites ( 
One of the girls of the third genera- 
tion, however, married a man who, 
though not himself affected, had affected 
cousins. From this union there are 
five children of the fourth generation, 
every one of whom shows the abnor- 
mality. 
From this and other cases the authors 
reach the conclusion “that the factor 
which determines the imperfect, brittle 
development of long bones is a dominant 
one. This conclusion is based on the 
fact that, as Griffith (1897) pointed out, 
the inheritance is generally direct, 7. ¢., 
does not skip a generation, but appears 
in one parent and in that parent’s 
parent. Since the trouble frequently 
shows itself only in early childhood 
there are, of course, the expected 
number of cases where a similar condi- 
tion is not known in either parent, 
37 
one or both of whom are perhaps dead. 
But even in such cases the trait is 
frequently recorded for a brother or 
sister just because they are contem- 
poraries. Beyond a certain point in 
the pedigrees, in any case, information 
must be lacking. What is to be 
expected on the hypothesis, and what is 
found, is that affected children rarely 
if ever arise from an unaffected parent 
and an affected grandparent.”’ 
CONSEQUENCES FOR EUGENICS 
“The consequences of this study for 
eugenics are these: A parent who is, or 
was in early life, osteopsathyrotic, will 
have half of his children similarly 
affected no matter whom he marries; 
except that if the consort also be osteo- 
psathyrotic it is to be expected that 
three-fourths of the children will be 
affected. But if neither parent has 
shown osteopsathyrotic tendencies then, 
no matter how frequent the tendency 
may be among their relatives, expecta- 
tion is that none of the children will 
have brittle bones. Moreover, where 
a parent is affected it is probable that 
his children will show the same tendency 
at about the same time in life, in the 
same bones, and to the same degree as 
he himself has shown it. As to how far 
that expectation should influence the 
reproduction of children the affected 
parent can best judge from his own 
experiences.” 
It will, of course, be understood that 
the proportions mentioned by the 
authors are merely averages, reached 
when large numbers are measured but 
not likely to be found exact in individual 
families. Their own study embraces a 
total of 150 persons, of whom eighty- 
three were affected. Thus they found 
55.3%, whereas expectation from larger 
numbers would have been, as they say, 
only 50%. 
The classification is admittedly rough, 
and it seems likely that under the 
name of osteopsathyrosis physicans 
have lumped a number of distinct but 
allied conditions that a geneticist would 
have separated. Or as the authors 
2 Hereditary Fragility of Bone (fragilitas osseus, osteopsathyrosis), by H. S. Conard and C. 
B. Davenport. 
November, 1915. Pp. 31, price 15 cents. 
Eugenics Record Office Bulletin No. 14, Cold Spring Harbor, Long Island, N.Y. 
