In February 1954 while doing his teaching at Harvard, Lashley unexpectedly collapsed and was hospitalized. He was later diagnosed with Hemolytic anemia and was put on a Cortisone treatment. The Cortisone eventually began to soften his vertebrae, and as a result a Splenectomy was performed. He was on the road to a full recovery until his trip to France with his wife Clair, where he once again unexpectedly collapsed, but this time to his death on August 7, 1958.[2]