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: We conclude that the administration of high doses of cefonicid or cefazedone to dogs can induce hematotoxicity similar to the cephalosporin - induced blood dyscrasias described in man and thus provides a useful model for studying the mechanisms of these disorders .
### Output Text:
We conclude that the administration of high doses of <span class="chemical">cefonicid</span> or <span class="chemical">cefazedone</span> to dogs can induce hematotoxicity similar to the <span class="chemical">cephalosporin</span> - induced blood dyscrasias described in man and thus provides a useful model for studying the mechanisms of these disorders . 