On the Action of Extract of Adrenal Cortex. 473 
is quite unknown from the northern parts of Australia or tropical Asia, so 
that it would appear to have reached Tasmania vid South America. The 
entire absence of a lofty mountain range like the Andes, running north and 
south through the tropics of the eastern hemisphere, has precluded the 
possibility of a temperate fauna from the north reaching temperate Southern 
Australia by that route. | 
Some Experiments made to Test the Action of Extract of Adrenal 
Cortex. 
By 8. G. SwHarrock and C. G. SELIGMANN.* 
(Communicated by John Rose Bradford, For. Sec. R.S. Received July 15, 1908.) 
In a recent communication, in which we discussed the significance of 
secondary sexual characters in the Fowl, we suggested that certain of these 
characters, ¢.g., the growth of spurs, “commonly regarded as essentially male, 
are not attributable to the function of the testicle alone, but possibly indicate 
| the concurrent action of some other gland, perhaps the adrenal, seeing that 
not a few examples of precocious puberty in children have been found 
associated with adenomatous or carcinomatous growths of the adrenal gland.”> 
We selected the cortex for experiment because the new growths 
occurring in these cases consist of cortical tissue, and because so litle 
is known of the physiological action of the cortex that there was nothing 
to negative the possibility referred to. The primary object of our experiments 
was to determine whether the injection of cortical extracts into young 
animals would hasten the appearance of secondary sexual characters, or exert 
any influence on the testicle. Since, however, there was no domestic animal 
smaller than the sheep, in which the male possesses well marked external 
secondary sexual characters, we were reduced to experiment on birds, selecting 
the common wild duck on account of the marked difference of plumage in the 
two sexes and the ease with which the bird can be kept in captivity. 
Besides the gradual passage from its nestling to its adult winter and 
breeding plumage, the male of this species presents a seasonal change. 
* The expenses of this research were defrayed by a grant from the Government Grant. 
Committee of the Royal Society. 
+ “ An Example of True Hermaphroditism in the Domestic Fowl,” ‘Trans. Path. Soc.,’ 
vol. 57, 1906, p. 109. The reason for excluding the testicle in this connection is that the 
growth of spurs is not inhibited by castration of the young bird. 2 
