Eckstein claims that at first a capsule of new connective tissue incloses the injected mass (Hart paraffin) a few days after the latter is injected, which can be easily stripped away from the encapsulated matter several weeks or months after, showing a smooth inner wall, the encysting capsule showing a decided lack of blood vessels, proving histologically its relation to the structure of cicatricial formation.

In this Eckstein is undoubtedly mistaken. He objects to the ultimate replacement with connective tissue for the vaselin process of Gersuny, when in reality we have begun to realize that such result will follow any hydrocarbon subcutaneous injection unless the latter be made in small quantity into parts of the body which are in constant motion.

The latter is shown with injections of paraffin made into or about the nasolabial fold. The tumor is so small as to be hardly felt by the palpating finger, but soon takes on larger proportions, evidencing an encapsulation of some extent or less independent of the encysted mass. That this is true can be ascertained by incising these little hard tumors when the contents can be readily pressed out or evacuated, the mass appearing practically as injected months before.

The same result is shown by Harmon Smith, who made an injection of paraffin (110° F.) into the peritoneal cavity of a rabbit which was killed twenty-two days later. On examination no sign of inflammation of the peritoneum was found—a fact that seems to prove the nontoxic effect of paraffin—nor were there evidences of the formation of adhesions. The mass had become rounded, had traveled about the abdominal cavity, and was found lodged between the liver and the diaphragm.

Comstock, with his experiences of injections of paraffins at high melting points, found that the harder paraffins do not become encysted, but become a part of the new tissue, which belief is corroborated by Downie, who introduced paraffin into a carcinomatous breast. Upon subsequent amputation and microscopic examination there was shown an intimate connection between the ramified site of the injection and the surrounding tissue. The same results have been noted by Jukuff.

Smith found that, in trying to remove an injected mass of paraffin several months after introduction, the greater part of the mass had become so thoroughly imbedded in the meshes of the newly formed connective tissue that it was practically impossible to remove it without including a considerable portion of the connective tissue as well.

Stein claims also that the paraffin is absorbed, little by little, as it is replaced by the new connective tissue, no matter what the melting point of the introduced paraffin might have been. The mass grows smaller to a degree, according to the amount injected; finally, at the end of a month or more, the entire mass is replaced by a tissue perceptibly analogous to cartilage.

Freeman, like Eckstein, claims that encystment of the paraffin occurs soon after the injection, much like that following a bullet or other foreign body in the tissues, but, unlike the latter author, that a limited amount of the connective tissue also penetrates the mass, which is speedily converted into a solid cartilagelike body.

Wendel believes entirely in the encystment theory, while Hertel, in specimens removed twelve to fifteen months after injection of paraffin with a melting point of 100° F., found a wall of round cells under various states of inflammation surrounding the masses with fibers of connective tissue traversing the latter. In the various histological findings he argues that the greater the tissue surface exposed to the injected foreign body the greater the irritation, and the larger the smooth paraffin mass the less the reaction; in other words, small masses of the injected mass cause a higher rate of tissue formation, while the larger masses have a tendency to encystment merely. He also believes that the harder paraffins require a greater length of time to become absorbed, and that during such time of resorption new connective-tissue growth is established, continuing to the time of its complete disappearance.

Comstock, after thorough and extensive investigation with the injection of paraffins of various melting points made at varying times after the injection of such procedures, concludes definitely that, “In paraffin we have a substance that will fill in spaces of lost tissue, and not remain entirely a capsulated foreign body, but become a bridgework, and, in fact, a part of the new tissue.”