To the Editor:—
The editorial, "The Multiple Causes of Paralytic Poliomyelitis," in The Journal, Sept. 10, 1960, page 175, is restricted to consideration of various types of virus as causes of this disease. In recent reports (Lennette and others: JAMA171: 1456-1464 [Nov. 14] 1959, and Brown and others: ibid.172:807-812 [Feb. 20] 1960), it was impossible to identify any type of virus in a relatively high percentage of cases.In this connection, it may be well to consider the results of studies by Trueta and Hodes (Lancet, May 15, 1954), who produced poliomyelitis by the simple procedure of injecting irritants—formol or croton oil—into the limbs of experimental animals, without using any kind of virus. If these results can be verified on a larger scale, it may become necessary to revise our present concepts of the cause of this disease, and direct our efforts toward a search for other