474 TUMORS. 



was present at some distant points not perceptible to clinical observation. 

 Every recurrent tumor, as a rule, takes on a more malignant type than the 

 preceding. Recurrence in internal organs after extirpation is considered to 

 be due to the fact that the tissues were already affected with the disease at 

 the time of the operation. 



A multiplication of benign tumors never occurs in internal organs, and what 

 was formerly considered a multiplication of chondroma, admits of a different 

 interpretation. A multiplicity of malignant tumors, both myeloma and 

 cancer, is often observed. Very probably this is due to a transportation of 

 tissue particles from the tumor, either directly into the vascular system (in 

 myeloma) or through the lymphatics and from them to the vascular system 

 (in cancer). These particles produce emboli in places where most numerous 

 and narrowest capillaries are found i. e., in the lungs and the liver. A sat- 

 isfactory proof of the presence of such emboli has not as yet been obtained, 

 neither do we understand why the embolized particles should infect the neigh- 

 boring parts and transform the normal tissues into a formation like them- 

 selves. Such secondary tumors are sometimes present in enormous quantities, 

 exhibiting the structure of the primary tumor. Not infrequently, however, 

 secondary tumors, after cancer, do not show a trace of the characteristic epi- 

 thelial structure of cancer, but that of myeloma. 



(~b) Histological Features. The examination of a tumor with 

 the microscope is of the utmost importance, as, in many instances, 

 it is only by an examination of this kind that a correct diagnosis 

 of the nature of the tumor can be obtained. 



In 1879 * I made the following statements : 



" I fully concur with Prof. Liicke, of Strassburg, in the opin- 

 ion that every practitioner should be acquainted with the minute 

 structure of tumors. Such knowledge would enable him to give 

 a more correct diagnosis and prognosis than is the case at 

 present. Very often we can decide the future of the patient 

 through microscopical examination of tumors, either after extir- 

 pation or before it, when small parts of the tumor are removed 

 for diagnostic purposes. 



"We know that there exists a series of tumors the benign 

 which do not materially interfere with the health of the 

 patient. Such tumors are either formations of connective tissue, 

 with fully developed basis-substance in its four principal varie- 

 ties viz.: myxomatous, fibrous, cartilaginous, or osseous; myx- 

 oma, fibroma, chondroma, and osteoma. Or they may be 

 composed of imitations of the fully developed tissues, sprung 

 from the middle germinal layer of the embryo, such as angioma; 

 lipoma, neuroma, myoma. Or, lastly, they may be combinations 



" The Aid which Medical Diagnosis receives from Recent Discoveries in 

 Microscopy." Archives of Medicine, vol. i., February, 1879. 



