GLOSSARY 251 



Rectum (Latin, rectus, straight). The last part of the 

 bowel terminating at the anus. 



Rennin. The enzyme found in the fourth stomach of 

 ruminants, and in the gastric juice of young mammals. 



Rods and cones. Structures in the external layer of the 

 retina. 



Rods of Corti. Specialized epithelium in the scala inter- 

 media of the cochlea. 



Schizomycetes (Greek, schizo, to split; mukes, mukatos, 

 a mushroom). Split fungi multiplying by fission. 



Secretin. A substance in the duodenum which, by 

 absorption into the blood, stimulates the pancreas to 

 secrete. 



Sero-therapy. The injection of specially prepared blood 

 serum in the treatment of various diseases. 



Skatol (Greek, skas, skatos, dung). A substance in faeces 

 arising from decomposition of proteids. 



Spermatoblast (Greek, sperma, semen ; blastano, to germi- 

 nate). Cells that form spermatozoa. 



Spermatozoa (Greek, sperma, semen ; zoon, an animal). 



Thymus (Greek, thumos, an onion). A blood gland of 

 early life found behind the breast bone. 



Thyro (Greek, thureos, a shield). Applied to thyroid 

 cartilage of larynx, and the thyroid body. 



Trophoblast (Greek, tropheo, to nourish ; blastos, a germ). 

 A portion of the epiblastic layers of the embryo that 

 has to do with the formation of the placenta. 



Urea (Greek, uron, uron). A crystalline substance found 

 in the urine. Uric acid. See text. 



Vaso-motor. Term applied to nerves that govern the 

 smaller arterioles. 



