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: Until the cause of the seizures was correctly identified , the patient was inappropriately treated with anticonvulsants .
### Output Text:
Until the cause of the seizures was correctly identified , the patient was inappropriately treated with anticonvulsants . 