Studies were made on the development and viability of eggs of the pig Ascaris under natural conditions in Peking.

• 实验证明,在北京地区的自然坏境中猪蛔虫卵从4月至10月都能进行发育,5月至9月间能发育成侵袭性幼虫期卵。在背阳光条件下为6月至8月。