ENDOCRINOLOGY IN PEDIATRICS 183 
HISTORICAL SUMMARY 
Although in the fifteenth century Paracelsus de- 
scribed his observations of cases of cretinism and 
goitre, yet the entire subject remained dormant until 
Johannes Muller and Ruysch, in 1844, showed that the 
blood received secretions from certain ductless glands. 
In 1849 Berthold, of Gottingen, experimented on ani- 
mals to ascertain the true nature of the ductless glands. 
Leydig, in 1850, described his work with the gonads; 
the intertubular connective tissue cells of the testes still 
bear his name—the “interstitial cells of Leydig.”’ The 
term “internal secretion” was first used by Claude Ber- 
nard in 1855, when he described the glycogenic function 
of the liver as its “sécrétion intérne.” The real begin- 
ning of ductless gland research dates back to 1855, 
when Thomas Addison described the syndrome caused 
by the changes in the adrenal glands. Starling, of Uni- 
versity College, London, gave us the term “hormone”— 
initiators or arousers of function—in 1902 in connec- 
tion with his epoch-making work with secretin, the 
duodenal internal secretion. Later, Sir Edward Schae- 
fer, of Edinburgh, distinguishes the hormones, which 
promote activities of another ductless gland, from the 
chalones, which have an inhibitory influence. 
Since Brown-Séquard’s first efforts to utilize testicu- 
lar extracts for therapeutic purposes and Berthold’s 
experiments on capons, in 1889, to determine the exist- 
ence of internal secretions in the sex glands, many theo- 
ries have been advanced to explain the individual func- 
tions of the ductless glands. It can be realized today 
how wide the field of activity is regarding ductless 
gland work—its therapy, physiological relation and 
activity—when the literature upon the subject is con- 
sulted. Within the past ten years endocrinology has 
taken on definite form as a real science, and is fast 
becoming one of the most important branches of med- 
