1. Blood from forty-one healthy volunteers, seventy-one patients with fractures but without symptoms of fat embolism and seven patients with clinical evidence of fat embolism was examined microscopically for fat droplets and chemically for triglycerides.

2. Fat droplets, after Millipore filtration of the blood, were seen evenly distributed in all three groups.

3. There was no significant difference in triglyceride concentration between serum and filtrate in the three groups.

4. The results do not support the thesis that the Gurd test is a reliable aid in the diagnosis of fat embolism.