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: Ten and 5 mg / kg i . v . ( + ) - cibenzoline suppressed digitalis - and adrenaline - induced arrhythmias , respectively .
### Output Text:
Ten and 5 mg / kg i . v . ( + ) - <span class="chemical">cibenzoline</span> suppressed <span class="chemical">digitalis</span> - and <span class="chemical">adrenaline</span> - induced arrhythmias , respectively . 