This study is concerned with a critical comparison of the passive transfer mechanisms of tuberculin and chemical contact hypersensitivities in the guinea pig by use of a four phase experimental approach.

This investigation involved isolation and characterization of specific antigenic materials from known species of Streptomyces. The resulting antigens were then used to establish serological relationships between a number of different species. These groupings were, in turn, compared with similar studies recently established by the ISP, in which other taxonomic criteria were used. By these means, the serological characteristics of the Streptomyces were evaluated for their potential utility as added taxonomic tools in the establishment of species designations within this group.

The role of operant behavior in the metabolism of brain 5-hydroxytryptamine (5-HT) turnover was investigated. Two and one-half hours following the administration of 150 mg/kg of para-chlorophenylalanine (PCPA), a specific inhibitor of tryptophan hydroxylase, levels of 5-HT were compared in sedentary and performing rats. Whole brain levels of serotonin were reduced in both responding and sedentary animals; however, differences between these groups were not statistically significant. The drug induced decrease in 5-HT levels was accompanied by a significant decrease in session responding. The degree of suppressed responding could be correlated with the level of 5-HT following PCPA, suggesting that the metabolism of serotonin is in part modulated by the rate of responding as maintained by the operant schedule.