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 the first , cobalt cardiomyopathy was induced in eight dogs ; VIP ( by radioimmunoassay ) decreased from 35 + / - 11 pg / mg protein ( mean + / - SD ) to 5 + / - 4 pg / mg protein ( P less than 0 . 05 ) .
### Output Text:
In the first , <span class="chemical">cobalt</span> cardiomyopathy was induced in eight dogs ; VIP ( by radioimmunoassay ) decreased from 35 + / - 11 pg / mg protein ( mean + / - SD ) to 5 + / - 4 pg / mg protein ( P less than 0 . 05 ) . 