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: With regard to spasm , the clinical findings are largely circumstantial , and the locus of cocaine - induced vasoconstriction remains speculative .
### Output Text:
With regard to spasm , the clinical findings are largely circumstantial , and the locus of <span class="chemical">cocaine</span> - induced vasoconstriction remains speculative . 