10 The Philippine Journal of Science 1922 
with these representatives varies slightly in quality and quantity in dif- 
ferent individuals and generations and that ‘the varying interaction is 
produced by the interference of factors which may or may not be trans- 
. mitted, such as those which may be conceived to account for the partial 
latency. 
This hypothesis explains not only the latency and the variation 
but also the quadruplicity and the symmetry of deformity. 
CONCLUSIONS 
From the study of our cases and our review of the literature 
we can endorse the following general conclusions: 
1. In the vast majorty of cases the deformity is quadruple. 
2. One foot is never malformed alone; the deformity is sym- 
metrical, and similar with individual variations. 
3. In the foot the first and fifth toes are the more constantly 
present. The fifth toe is always present, while the first is in 
some cases missing. 
4, Crossed bones are never found in the feet. 
5. The hands are never affected if the feet are not malformed; 
in a few cases both feet and one hand are deformed. 
6. There is generally metacarpal or metatarsal hypoplasia 
when the phalanges are absent. 
7. Ectrodactyly generally affects the second or third toe. 
8. Ectrodactyly proceeds from the radial side, avoiding bones 
as it approaches the ulnar side. In some cases only the little 
finger is present. | 
9. Ectrodactyly is léss commonly associated with polydactyly 
than with syndactyly. 
10. Syndactyly is generally confined to the fourth and fifth 
digits of either hands or feet. 
ACKNOWLEDGMENTS 
For assistance in the preparation of this paper We are in- 
debted to Dr. Otto Schébl, of the Bureau of Science, and to the 
departments of medicine and of physical therapy of the Philip- 
pine General Hospital. 
BIBLIOGRAPHY 
ANDERSON, W. Brit. Med. Journ. (June, 1886) 1107. 
BAILEY, F., and Minter, A. Text-book of Embryology. New York, William 
Wood & Co. 3d ed. (1916) 611. : 
Dowp, C. N. Ann. Surg. 24 (1896) 211. 
Fippes, J. D. Anat. Anz. 14 (1912) 544. 
FoTHERBY, H. A. Brit. Med. Journ. (May, 1886) 975. 
HASSELWANDER, A. Zeitschr. f. Morphol. u. Anthropol. 6 (1908) 511. 
