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: He was brought directly to a hospital where he was found to be agitated and confused with shivering , myoclonic jerks , rigidity , salivation and diaphoresis .
### Output Text:
He was brought directly to a hospital where he was found to be agitated and confused with shivering , myoclonic jerks , rigidity , salivation and diaphoresis . 