Scanning electron micrographs of Heligmosomoides bakeri adult worms exposed to papaya latex and ficin in vitro. Clear evidence of damage to the cuticle can be seen from 30 min in 200 μM crude papaya latex and ficin, 30 μM. Note the transverse wrinkling leading to signs of shedding of the cuticle after 90–120 min. In contrast, worms incubated in Hanks's saline showed no sign of cuticular damage, even after 120 min incubation. Scale bar = 10 μm. For SEM preparation adult specimens of Heligmosomoides bakeri were fixed in glutaraldehyde, postfixed in osmium tetroxide, critical point dried and gold coated before examining in a Jeol JSM 840 scanning electron microscope. For further details see Stepek et al . Reprinted with permission.