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: Causes of death , with special reference to cerebral haemorrhage , among 240 patients with pathologically verified Parkinson ' s disease were investigated using the Annuals of the Pathological Autopsy Cases in Japan from 1981 to 1985 .
### Output Text:
Causes of death , with special reference to cerebral haemorrhage , among 240 patients with pathologically verified Parkinson ' s disease were investigated using the Annuals of the Pathological Autopsy Cases in Japan from 1981 to 1985 . 