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: In addition to our highlighted cases , we review the history , classification , pathophysiologic features , and treatment of milk - alkali syndrome and summarize the cases reported from early 1995 to November 2003 .
### Output Text:
In addition to our highlighted cases , we review the history , classification , pathophysiologic features , and treatment of milk - alkali syndrome and summarize the cases reported from early 1995 to November 2003 . 