have often been regarded as parasitic, though many such cases deal 
with insects incapable of such parasitism and often found to be dead 
Fig. 67. Seed of Indian mustard, Brassica juncea. Enlarged. From Beal, 1910. 
and partly digested when carefully examined. 
A third group of spurious parasites consists of portions of the host 
Fig. 68. Seed of shepherd’s purse, Bursa bursapastoris. Enlarged. From Beal, 1910. 
structure, such as ciliated tracheal cells which have been regarded 
as causative organisms in whooping cough, or lymphatic glands and 
Fig. 69. Seed of daisy fleabane, Erigeron ramosus. Enlarged. From Beal, 1910. 
pacchionian bodies which have been regarded as hydatids. 
A fourth group of spurious parasites, and one of especial interest 
Fig. 70. Seed of bird’s foot trefoil, Lotus corniculatus. Enlarged. From Beal, 1910. 
in connection with spurious parasites in feces, is composed of plant 
and animal material which may be mistaken for parasites and parasite 
60 
