No deed conveying lands nor any instrument required or allowed by law to be registered, executed by husband and wife since the eleventh of March, 1889, if the acknowledgment or private examination of the wife is thereto certified as prescribed by law, shall be invalid because its execution or acknowledgment was procured by fraud, duress or undue influence, unless it is shown that the grantee or person to whom the instrument was made participated in the? fraud, duress or undue influence, or had notice thereof before the delivery of the instrument. Where such participation or notice is shown, an innocent purchaser for value under the grantee or person to whom the instrument was made shall not be affected by such fraud, duress or undue influence. (1889, c. 389; 1899, c. 235, s. 10; Rev., s. 956; C.S., s. 1001; 1945, c. 73, s. 7.)