752 HARVARD LAW REVIEW has been presented for admission to the class of commercial paper, those courts have called for their guidance men from the actual business world, best qualified to speak on the subject. If, from their evidence, it has appeared that the instrument in question was by the general custom and practice of the business world treated as a negotiable instnunent, the court has given effect to that usage, and adjudged the instrument to be subject to the same law as other negotiable paper. This was true not only in the early and formative periods of the commercial law, com- ing down to the age of Lord Mansfield, but has been followed with the same freedom from time to time down to the current year. Those courts have never forsaken the business world to pursue a definition." Consequently, we must always interpret the formal requisites with our eyes upon the actual conduct of life, continually testing them by the ultimate purpose of negotiable instruments, free cir- culation as a substitute for money. In other words, a formal requi- site is only a concise statement of a method for avoiding the evils of uncertainty, and when those evils do not arise the requisite cannot properly be said to be violated. The formal requisites which may conceivably render invalid in- strmnents with acceleration provisions are three in nimiber: the sum payable must be a sum certain; ^ the instrument must be pay- able on demand, or at a fixed or determinable future time; ^ it must not contain an order or promise to do anything in addition to the payment of money. ^° Of these, the second is the most important and must be fully considered at once. The other two will be dis- cussed subsequently. Much of the confusion in the cases is due to the failure of the courts and textbooks ^^ to distinguish between the requisite of cer- tainty of time and that which forbids the instrument to be condi- tional.^^ Some instruments violate both requisites. For instance, if a note is payable when the maker marries, it is conditional since he may never marry, and furthermore, if he does the time of pay- ' Negotiable Instruments Law, §§ i (2), 2; 2 Ames, Cases on Bills and Notes, 830; I Daniel, Negotiable Instruaients, 6 ed., § 53. 8 Negotiable Instruments Law, §§ i (3) , 4; 2 Ames, Cases on Bills and Notes, 831. " Negotiable Instruments Law, § s; 2 Ames, Cases on Bills and Notes, 829; I Daniel, Negotiable Instruments, 6 ed., § 59. " An example is i Daniel, op. cii., Chap. II, Section III. ^ Negotiable Instruments Law, §§ i (2), 3; 2 Ames, Cases on Bills and Notes^ 827.
