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: Iridocyclitis was seen most frequently in young female patients ( 0 to 4 years ) with the monoarticular or pauciatricular form of the arthritis .
### Output Text:
Iridocyclitis was seen most frequently in young female patients ( 0 to 4 years ) with the monoarticular or pauciatricular form of the arthritis . 