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: Injections of scopolamine into mice resulted in impaired performance on Y - maze tests ( a 37 % decreases in alternation behavior ) .
### Output Text:
Injections of <span class="chemical">scopolamine</span> into mice resulted in impaired performance on Y - maze tests ( a 37 % decreases in alternation behavior ) . 