Intense acid-phosphatase activity was found in the distal parts of the cells lining the entire length of the vas deferens of the domestic cock and there was evidence that the enzyme(s) is secreted in large amounts into the seminal plasma. Some acid phosphatase(s) was also produced in the vasa efferentia and seminiferous tubules.
Intense alkaline-phosphatase activity was found only in secretions of certain parts of the vasa efferentia, in the tunica intima of all small blood vessels and in intertubular tissue. From the evidence, it is considered that some alkaline phosphatase(s) might possibly diffuse into the seminal plasma from all regions of the genital tract, but it is likely to be small in amount. The significance of the presence of phosphomonoesterases in seminal plasma is discussed.