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: A 24 - h pretreatment of both rats and mice with a single dose of CS ( 100mg / kg , i . p . ) , resulted in significant protection against the hepatotoxic effects of CCl4 , CHCl3 , acetaminophen and galactosamine and against the lethal ( and presumably cardiotoxic ) effect of adriamycin administration .
### Output Text:
A 24 - h pretreatment of both rats and mice with a single dose of <span class="chemical">CS</span> ( 100mg / kg , i . p . ) , resulted in significant protection against the hepatotoxic effects of <span class="chemical">CCl4</span> , <span class="chemical">CHCl3</span> , <span class="chemical">acetaminophen</span> and <span class="chemical">galactosamine</span> and against the lethal ( and presumably cardiotoxic ) effect of <span class="chemical">adriamycin</span> administration . 