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 results showed that rats treated with Morphine / Rg1 decreased escape latency and increased the time spent in platform quadrant and entering frequency .
### Output Text:
The results showed that rats treated with <span class="chemical">Morphine</span> / <span class="chemical">Rg1</span> decreased escape latency and increased the time spent in platform quadrant and entering frequency . 