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: Codeine catalepsy was increased by clonidine and decreased by naphazoline and xylometazoline .
### Output Text:
<span class="chemical">Codeine</span> catalepsy was increased by <span class="chemical">clonidine</span> and decreased by <span class="chemical">naphazoline</span> and <span class="chemical">xylometazoline</span> . 