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: On the other hand , mydriasis , tremor and clonic - tonic convulsions evoked by carbachol and eserine were not significantly changed by calcium chloride .
### Output Text:
On the other hand , mydriasis , tremor and clonic - tonic convulsions evoked by <span class="chemical">carbachol</span> and <span class="chemical">eserine</span> were not significantly changed by <span class="chemical">calcium chloride</span> . 