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: In response to this a marked jaw stiffness occurred which lasted for two minutes and the anaesthesia were terminated .
### Output Text:
In response to this a marked jaw stiffness occurred which lasted for two minutes and the anaesthesia were terminated . 