It is becoming more and more apparent from various studies on growth and metabolism that the two sexes must be thought of as responding differently to the same environmental conditions. As this knowledge becomes more detailed, and more delicate means of analysis are devised, probably the chemical constitutions of the male and female mammal will be accurately differentiated. From this point of view, I should like to record a rather simple case which has recently come under observation.
A number of dogs were bred under carefully regulated conditions and a striking difference between the development of rickets in males and females was found. An American fox-hound bitch whelped eight pups on Oct. 19, 1926. She was an excellent mother and nursed and cared for the pups in a normal manner. There were four males and four females in the litter. One male died when 2 days old from an unknown
STOCKARD CR. RICKETS IN DOGS AS PROBABLY RELATED TO SEX. Am J Dis Child. 1928;36(2):310-314. doi:10.1001/archpedi.1928.01920260118007