Cancer and its complications / by Charles Egerton Jennings.

  • Jennings, Charles Egerton.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Cancer and its complications / by Charles Egerton Jennings. Source: Wellcome Collection.

    15/170 (page 5)
    CHAPTER II. THE VARIETIES OF CANCER. CANCERS are divided into two main groups, the carcino- mata and the sarcomata, each of which presents sub- varieties. This mode of classification is based upon the circumstance that during the development of the embryo, the blastoderm presents three layers, viz. the epiblast, mesoblast, and hypoblast. Embryology teaches us, that from the cells of which the trilaminar blastoderm consists (all having arisen from a common parent cell, the ovum) eventually is developed the entire body, all parts of which can be traced in origin to one of the three layers mentioned. When a cancer originates from a part of the body developed from either hypoblastic or epiblastic cells the growth is termed a carcinoma; if from cells derived from mesoblastic tissue, a sarcoma. Carcinomata are composed of groups of epithelial cells imbedded in a vascular framework of connective tissue. The cells multiply endogenously, and lie together in confused masses. The sarcomata which arise from parts derived from the mesoblast are composed of cells which do not ordinarily lie in alveoli, or spaces, (as in the case of the carcinomata) ; the cells predominating over the intercellular substance, thus resembling immature connective tissue. So far, the division between the two main groups of cancer can be formed easily enough, but unfortunately it is not always practicable to say from which of the blastoderm layers a neoplasm has arisen. Moreover, enccphaloid carcinoma (so-called) is perhaps generally a sarcoma, and the rare cases of alveolar sarcoma are most difficult to distinguish