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: Kindled seizures were induced by daily administration of 60 mg / kg cocaine for 5 days .
### Output Text:
Kindled seizures were induced by daily administration of 60 mg / kg <span class="chemical">cocaine</span> for 5 days . 