William Beaumont expressed a narrow view on the role of saliva, suggesting that its primary function is to lubricate food for easier passage down the esophagus. While this perspective captures one aspect of saliva's role in digestion, it overlooks the complexity of its functions. Beaumont's beliefs reflect an understanding limited by the knowledge of his time.

In Mary Roach's book "Gulp: Adventures on the Alimentary Canal," she critiques Beaumont's assertion, suggesting that saliva serves many more purposes beyond simple lubrication. Roach emphasizes the significance of saliva in various digestive processes and its essential roles in oral health, taste, and overall digestion, illustrating that Beaumont's understanding was indeed limited.