A comparative study of six hydrolases, acid and alkaline phosphatases, aryl sulphatase, beta-glucuronidase cholinesterase, and non-specific esterase, was carried out on the tissues of normal healthy and Frescon-treated Bulinus. The presence and activity of these enzymes in the tissues of normal animals were taken to indicate the probable functions of the tissues concerned. Frescon administration caused inhibition of acid phosphatase and also induced the release of cholinesterase and non-specific esterase in some tissues. It is concluded that the most important effects of Frescon on snail physiology are the disorganization of neuronal function and disturbance of olfactory activity.
