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: Pyrrolidine dithiocarbamate protects the piriform cortex in the pilocarpine status epilepticus model .
### Output Text:
<span class="chemical">Pyrrolidine dithiocarbamate</span> protects the piriform cortex in the <span class="chemical">pilocarpine</span> status epilepticus model . 