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: Evans Blue ( mug g - 1 of brain tissue ) was greater in the 90 / HTN group ( 24 . 4 + / - 6 . 0 ) versus the control group ( 12 . 3 + / - 4 . 1 ) , which was in turn greater than the 15 / HTN group ( 7 . 3 + / - 3 . 2 ) .
### Output Text:
<span class="chemical">Evans Blue</span> ( mug g - 1 of brain tissue ) was greater in the 90 / HTN group ( 24 . 4 + / - 6 . 0 ) versus the control group ( 12 . 3 + / - 4 . 1 ) , which was in turn greater than the 15 / HTN group ( 7 . 3 + / - 3 . 2 ) . 