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: This study assessed the effect of normal aging on ( 1 ) the tropicamide - induced increase in pupil diameter , and ( 2 ) the reversal of this effect with pilocarpine .
### Output Text:
This study assessed the effect of normal aging on ( 1 ) the <span class="chemical">tropicamide</span> - induced increase in pupil diameter , and ( 2 ) the reversal of this effect with <span class="chemical">pilocarpine</span> . 