In addition to acephalocysts, to which we have already referred, the Cysticercus is by no means of rare occurrence in the heart, being then also simultaneously present in some of the voluntary muscles. There are seldom more than one or a very few of these worms to be found together in the substance of the heart; and in these cases they are also commonly present in the brain.

The Trichina, unlike the cysticercus, does not occur in the heart, although it exists in the voluntary muscles.

In addition to the above-named secondary formations we will here notice certain morbid structures which appear in the cavities of the heart, either free or adhering. These are not products of the endocardium, but essentially fibrinous concretions from the blood, and differing, therefore, from the above secondary formations, both in this and other respects. They constitute a series of formations which we will consider under the following title: