For some journals and books, article and chapter records have been added to BHL.  You may see "View Identified Parts" links on BHL records.  This link will show the identified articles or chapters for a volume. 

Article and chapter records are searchable in the catalog, using either basic or advanced search. 
Example citation:
Forbes, Stephen A. "The Ecological Foundations of Applied Entomology." Annals of the Entomological Society of America 8, no. 1 (1915): 1-19.
Search results include the source title, pages, and other details of the publication. 
"View Metadata" links to the catalog record, and the hyperlinked title goes to the first page of the article in the digitized volume.

Catalog record:

Article view:

But it is important to remember that not all articles and chapters in BHL have been cataloged. 
When a catalog search for an article fails, try a full text search. 

Example citation: Forbes, S. A. “The Simulium-Pellagra Problem in Illinois.” Transactions Congress of Entomology Oxford 2 (1913): (477-485).

Try a full text search instead:

Results can include the volume containing the article and other items in which the work is cited or mentioned. Use information from the citation, to identify the correct item. 

Open the item and navigate to page 477 (from the citation):