1815—1846 年间英国谷物法的变革是保护贸易制度向自由贸易制度过渡的一个典型案例。本文通过对这段历史史实的重新考察和分析, 揭示了收入分配成本相对变动原理, 它可以解释国家农产品贸易政策的演变。英国政府在特定的历史背景下, 选择谷物法而不是自由贸易下的转移支付来实现粮食安全和社会稳定, 并可以节约分配成本。1815—1846年间, 英国政治、经济环境的变化使谷物法的分配成本—收益发生改变, 边际上的积累最终导致了谷物法的废除。这种渐进的、积累的变革方式, 为英国农业的发展提供了一个稳定的制度环境。对这段历史的回顾, 具有重要的现实意义: 它为探讨在WTO 的背景下中国如何实现粮食安全提供了一个新的思路。

The most important step in the reform of state-owned onterprises in China is to restructure the unitary state-owned and state-managed property right. This proparty right reform is the first and key step in the state-owned enterprises’ institutional change, but it isn’t the last and sole important step. After the first step in the property right reform, what can do in the further reform governments different levels as the main concrete operating body? What is the gain or loss for governments? And which characteristics has their behavior? This paper has made an analysis based on the reform of medium and small-sized state-owned enterprises in Zhucheng city, Shandong provcnce as a case and on some principles of new institutional economics as a means. The reform in this countv-level city was selected as a case because of the following reasons: the first is the large scope and the great effect of the reform; the second is its value to study the large drop of the status and the role of governments in the reform; and the third is the enterprises’ institutional change in Zhucheng continued after the state property right has been fundamentally restructured, so it is worthy to be further followed and studied.

本文结合中国和其他一些转型国家市场化改革的经验事实，提出并验证了关于制度变迁的三个新的理论假说：（1）同一轨迹上制度变迁的边际收益先递增递减，其变化轨迹呈倒“U”型曲线；（2）政府行政力量推动市场化改革在一定时期内是可行的，有效的；（3）制度变迁中不同主体的角色定位和转换主要取决于制度变迁对各自利益的影响，也受制于其他因素。