A morphological study of antibody transport in the transparent fluid flowing form the lymph-folds of the copulatory organ into the cloacal lumen of the cock (Gallus domesticus).

The lymph of the copulatory organ of the cock is produced mainly in the lymphobulbus phalli. The lymph fluid passes the secretory duct with its branching lymph capillaries and discharges into the lymph-fold. From here, it is released into the interstitial tissue through gaps of the lymph capillaries but also through the intercellular spaces between the endothelial cells of the lymph capillaries. A minor portion of the lymph is produced also in the lymph-fold from where it is transported in the interstitial tissue either by transfer vesicles of the circulatory blood capillaries or by pores and fenestrae of the transudatory blood capillaries. During the erection of the copulatory organ the lymph is pressed through the intercellular spaces of the epithelial covering the lymph-fold which is cylindrical and multistratified in shape. From here, it reaches the cloacal lumen in the form of transparent fluid (TF). TF was collected by different methods. It contains immunoglobulins which arise from plasma cells of the lymph-fold. Juxtaluminally, the lymph passage takes place via zonulae pseudooccludentes. The epithelial covering secretes a mucoid substance which is added to the TF prior to its following the spermatic phase as the final fraction of the ejaculate. Plasma cells and lymphocytes migrate along the lymph flow in the intercellular spaces of the epithelial covering of the lymph-fold. After an experimental application of antigen the sub- and intraepithelial cells and lymphocytes increase in number with their portion of active cells exceeding the less active ones. The increase coincides with the increase in antibodies detected in the TF where they may cause a local immunisation.