In what has gone before, the changes referred to have mainly concerned the blood-vessels and the various channels and spaces of the lymphatic system in connection with them. Besides these, however, we have to consider the changes in the tissues themselves, whether it be the proper parenchyma or the supporting structures forming the connective tissue. The proper tissue-changes are divisible in a general way into two, namely, those which concern the parenchyma or proper substance of organs, and which may be termed parenchymatous changes, and those which involve a new-formation of tissue and are met with chiefly in the connective tissues and the surface epithelium.