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: Induction studies have further shown that while pretreatment of 3 - methylcholanthrene ( MC ) , an inducer of P4501A1 / 1A2 , did not produce any significant effect in the incidence of lindane induced convulsions , pretreatment with phenobarbital ( PB ) , an inducer of P450 2B1 / 2B2 or ethanol , an inducer of P450 2E1 catalysed reactions , significantly increased the incidence of lindane induced convulsions .
### Output Text:
Induction studies have further shown that while pretreatment of <span class="chemical">3 - methylcholanthrene</span> ( <span class="chemical">MC</span> ) , an inducer of P4501A1 / 1A2 , did not produce any significant effect in the incidence of <span class="chemical">lindane</span> induced convulsions , pretreatment with <span class="chemical">phenobarbital</span> ( PB ) , an inducer of P450 2B1 / 2B2 or <span class="chemical">ethanol</span> , an inducer of P450 2E1 catalysed reactions , significantly increased the incidence of <span class="chemical">lindane</span> induced convulsions . 