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: The current data showed that pilocarpine significantly delayed onset of arrhythmias , decreased the time course of ventricular tachycardia and fibrillation , reduced arrhythmia score , and increased the survival time of arrhythmic rats and guinea pigs .
### Output Text:
The current data showed that <span class="chemical">pilocarpine</span> significantly delayed onset of arrhythmias , decreased the time course of ventricular tachycardia and fibrillation , reduced arrhythmia score , and increased the survival time of arrhythmic rats and guinea pigs . 