Rapisardi-Mirabelli, A. Keywords: International organizations | Mots clefs: Organisations internationales | ABSTRACT A. Rapisardi-Mirabelli points out that the legal institutions, known as International Unions, were the first, scattered, and rudimentary cores of an organization of the League of States. The author begins with a general presentation of this phenomenon. He then replies to the remarks that international Unions were merely collective treaties with the accession clause. The author later studies t…