"To say that only those businesses affected with a public interest may be regulated is but another way of stating that all those businesses which may be regulated are affected with a public interest"

This quote by Harlan Stone is suggesting that businesses that are regulated by the federal government are those that remain in the general public passion. To put it simply, services that are managed by the federal government are those that have an effect on the public, either straight or indirectly. This could include companies that give necessary solutions, such as energies, or those that have a huge impact on the environment. By regulating these organizations, the government is guaranteeing that the public is protected from any potential harm that could be triggered by these businesses. This quote is likewise recommending that organizations that are not managed by the federal government may not always remain in the general public interest, and also therefore, might not undergo the same regulations.