In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: OUTCOME MEASURES : Pupil size at time points after administration of tropicamide and pilocarpine ; scopolamine - induced impairment in word recall .
### Output Text:
OUTCOME MEASURES : Pupil size at time points after administration of <span class="chemical">tropicamide</span> and <span class="chemical">pilocarpine</span> ; <span class="chemical">scopolamine</span> - induced impairment in word recall . 