What is the ruling on eating the brain, eyes, heart, kidneys, tongue, and intestines of a slaughtered animal, and what is the criterion for distinguishing between what is permissible of blood and what is forbidden of meat?

A lawfully slaughtered animal is permissible to eat in its entirety, except for the flowing blood. The aforementioned Hadith indicates the prohibition of carrion (except for fish and locusts) and blood (except for the liver and spleen). It does not mean that all blood is permissible and all meat is forbidden.