REPRODUCTION IN MAN 93 



In order to bring the sperms In contact with the 

 ova within the body of the mother special struc- 

 tures have been developed. In man these special 

 structures are the penis and three special sets of 

 glands, each with a separate work to do. These 

 are called respectively Cowper's, the prostate, 

 and the seminal vesicles. 



An illustration may help us to understand the 

 action of the glands. It is common experience to 

 have the mouth water in anticipation of something 

 delectable to eat. A watery fluid appears in the 

 mouth in response to a stimulus from the brain. 

 This stimulus is carried by nerves to the salivary 

 glands located in the side of the mouth and also 

 just beneath the ear. These glands manufacture 

 a definite secretion which serves a useful purpose 

 in the digestion of food. All secretions are made 

 in living protoplasm that has become specialized to 

 produce a specific product. Such glands do not act 

 rhythmically or in an intermittent fashion but con- 

 tinuously. Their rate of activity depends in the 

 main on the physical vigor and the demands upon 

 the glands for their product. The sex glands pro- 

 duce their secretions in just the same manner as 

 the salivary, pancreas or liver. The only dis- 

 tinction is in the use to which nature puts their 

 products. 



There is still one more fact to be kept in mind as 

 we think of the activity of glands. In all nature 



