Interlineation \In`ter*lin`e*a"tion\, n. [Cf. F.
   interlin['e]ation.]
   [1913 Webster]
   1. The act of interlining.
      [1913 Webster]

   2. That which is interlined; a passage, word, or line
      inserted between lines already written or printed.
      [1913 Webster]

INTERLINEATION, contracts, evidence. Writing between two lines.
     2. Interlineations are made either before or after the execution of an 
instrument. Those made before should be noted previously to its execution; 
those made after are made either by the party in whose favor they are, or by 
strangers. 
     3. When made by the party himself, whether the interlineation be 
material or immaterial, they render the deed void; 1 Gall. Rep. 71; unless 
made with the consent of the opposite party. Vide 11 Co. 27 a: 9 Mass. Rep. 
307; 15 Johns. R. 293; 1 Dall. R. 57; 1 Halst. R. 215; but see 1 Pet. C. C. 
R. 364; 5 Har. & John; 41; 2 L. R. 290; 2 Ch. R. 410; 4 Bing. R. 123; Fitzg. 
207, 223; Cov. on Conv. Ev. 22; 2 Barr. 191. 
     4. When the interlineation is made by a stranger, if it be immaterial, 
it will not vitiate the instrument, but if it be material, it will in 
general avoid it. Vide Cruise, Dig. tit. 32, c. 26, s. 8; Com. Dig. Fait, F 
1. 
     5. The ancient rule, which is still said to be in force, is, that an 
alteration shall be presumed to have been made before the execution of the 
instrument. Vin. Ab. Evidence, Q, a 2; Id. Faits, U; 1 Swift's Syst. 310; 6 
Wheat. R. 481; 1 Halst. 215. But other cases hold the presumption to be that 
a material interlineation was made after the execution of an instrument, 
unless the contrary be proved. 1 Dall. 67. This doctrine corresponds nearly 
with the rules of the canon law on this subject. The canonists have examined 
it with care. Vide 18 Pick. R. 172; Toull. Dr. Civ. Fr. liv. 3, t. 3, c. 4, 
n. 115, and article Erasure.