Neoplasms 375 



connective tissue. Ordinary healthy connective tissue is formed from 

 cells which have undergone ^ process of transition from cellular 

 to fibrous condition. In sarcomatous tissue, these cells show a 

 tendency to continuous proliferation instead of the formation of 

 fibrous traheculae. Consequently, the consistence of sarcomata is 

 usually soft, but they may be mixed with more or less fibrous tissue, 

 when they are hard. They are often enclosed by a capsule, but fre- 

 quently infiltrate neighboring tissues. They are very prone to un- 

 dergo partial or complete mucoid changes. The partially de- 

 generate form is described as "sarcoma myxomatodes." Instances 

 have been recorded by Creighton. 



The Sarcomata occur with less frequency than the 

 carcinomata, Froehner placing their percentage at six or seven, 

 but they are equally variable in appearance. A mixed form is rather 

 common, such as fibro-,chondro-,osteo-,lympho-,myo^, and myxo- 

 sarcomata. In their gross appearance the sarcomata often manifest 

 a close resemblance to the carcinomata. They are remarkable for 

 their development in young as well as adult dogs, for their rapidity 

 of growth (some, however, grow slowly), their soft consistence 

 (some are also hard), their partiality for periosteal surfaces, their 

 inclination to metastasis, and their tendency to ulceration when 

 located in the skin and mucous membranes. Metastatic dissemina- 

 tion is mostly by the veins and particles becoming detached to be 

 carried along as emboli. By reason of this it is a common thing 

 to find secondary sarcoma in the lung or even right heart, and where 

 the portal vein is invaded, the liver. The tendency to ulceration 

 is probably dependent on the incompatibility of nutrition with 

 rapidity of growth. 



Primary Sarcoma exhibits a predilection for the Frontal Re- 

 gion, the Superior Maxilla, the Sternum, Bones of the Extremities, 

 the Skin, the Muscles, and the Mammary gland. Other organs 

 sometimes invaded are the Nasal Bones (Kitt), the Testes (Siedam- 

 grotzky), the Vagina, the Uterus (Moeller), the Heart (Cadiot, 

 Bourney, Kitt, Johne), the Thyroids (Cadiot), the Lungs and Pleura 

 (Cadeac, Kitt, Leisering), the Stomach (Benoit, Megnin), the In- 

 testine (Petit), the Omentum (Siedamgrotzky), and the Peritoneum 

 (Bournay)." The cases of round-cell sarcoma of the Penis and 

 Vagina described by Smith & Washbourn are of very great interest, 

 but there is some doubt as to whether they were dealing with ex- 



