Studies on Hymenolepis microstoma in vitro. II. Effect of yeast extract on development and maturation.

Four day old in vivo Hymenolepis microstoma were cultured in vitro for 6 days in media containing 2, 1, 0.5 and 0.1% yeast extract. Worms from all groups including control group increased in length and produced nearly equivalent numbers of proglottids. However, worms grown in yeast extract added media produced significantly more mature proglottids and were heavier than those in the control medium. The possibility of pyridoxin involvement has been contemplated. Effects of osmotic pressure and pH on the development of worms are discussed.