About 1920, many physicians began to lose interest in operating a clinical laboratory, primarily because of the complexities of the shaking machine and the reagents used to perform tests for syphilis. Thus, the clinical pathologist appeared (according to some unkind wits they were another complication of syphilis) as the physician with the interest, time, and skill to master the rapidly increasing complexities of the medical laboratory. In the early 1930s the American Society for the Control of Cancer recommended that there should be at least one pathologist in each state, "thoroughly competent to recognize malignancy." Thus, the surgeons gradually stopped doing their own surgical pathology, though an unrelenting few did not relinquish this activity to the anatomic pathologist until the 1950s.
If you started practicing hospital laboratory medicine in the 50s, you will recall your long-term campaign to get the hospital to buy its first spectrophotometer costing several hundred dollars.
Stevenson GF. The Small Office Laboratory in the Cycle of Laboratory Medicine: Reinventing the Magic Black Box. JAMA. 1985;254(20):2949-2951. doi:10.1001/jama.1985.03360200101040