Goblet cell impressions free from epithelial cells could be collected
more consistently from the rabbit conjunctiva by creating a space betw
een the applied cellulose acetate filter and the tissue surface. Succe
ssive impressions taken over the same region of the conjunctiva could
not be matched. When tight control of the area being sampled was estab
lished, the impressions left by cells on successive filters varied wid
ely in intensity.