As Auspitz, Unna, and many others have pointed out, the term papilloma is, histologically speaking, a grave misnomer, for the real development is in the rete and the papilla are only secondarily affected. If all tumors arising from squamous epithelium are to be spoken of as epitheliomata, we must call malignant epithelial tumors of the lip, tongue, pharynx, esophagus, and of certain portions of the genital tract, epitheliomata. To the author this seems undesirable for two reasons; first, because these tumors run the same course as the glandular carcinomata; and, secondly, because the term carcinoma means more to both physician and laity than does the word epithelioma, especially since the latter is sometimes used to designate a benign growth.

Krompecher,* in his excellent monograph, "Der Basalzellenkrebs adopts the following classifications:

1. Fibroepithelioma spinocellulare simplex, or keratodes.

2. Carcinoma spinocellulare simplex, or keratodes.

3. Fibroepithelioma basocellulare.

Bloodgood,* after a characteristic thorough search of the literature, advocated the following scheme in his teaching and for his specimens :

1. Benign epithelial warts.

a. Mixed epithelial warts.

b. Spinocellular (horny) warts.

c. Basocellular warts.

2. Malignant epithelial warts.

a. Epithelioma spinocellulare malignum.

b. Epithelioma basocellulare malignum.

3. Malignant basocellular tumors.

a. Epithelioma basocellulare solidum malignum.

b. Epithelioma basocellulare solidum et adenoides malignum.

c. Epithelioma basocellulare solidum et adenoides cysticum malignum.

d. Carcinoma basocellulare solidum stellatum.

4. Carcinoma cubocellulare.

*Krompecher: Der Basalzellenkrebs, Jena, 1903.

*Bloodgood: Progressive Medicine, December, 1904.

5. Epithelioma spinocellulare malignum. i.

6. Carcinoma spinocellulare malignum.

7. Adenocarcinoma of hair follicles.

8. Adenocarcinoma of sweat glands.

Here the author seriously objects to Bloodgood's differentiation of malignant tumors, having the same origin, into epitheliomata and carcinomata according to slight differences in their histological picture. Bloodgood uses the term epithelioma when the growth has retained the picture of the tissue from which it sprang, and carcinoma when the picture of the original tissue can no longer be distinguished. In some tumors certain sections will, however, resemble epithelioma, and other sections, perhaps only a short distance away, will resemble carcinoma, and hence this differentiation does not appeal to the writer as being practical. The spinocellular warts are not necessarily horny warts; here there seems to be some confusion with the keratomata. Otherwise, however, Bloodgood's pathological classification is extremely good. In addition to giving us a working differentiation, Bloodgood has also shown exactly how the pathology of a neoplasm agrees with its clinical course, and hence with its treatment. He has added a most important chapter to the study of Jthe malignant cutaneous tumors.

In an attempt to give a simpler classification, Bloodgood has recently devised the following classification:

1. Benign precancerous lesions.

a. Warts, which include any epithelial hypertrophy.

b. Subepidermal nodules, often sebaceous gland infections.

c. Ulcers, as tuberculous, syphilitic, etc.

d. Sinuses, unhealed.

2. Early cancers.

a. Malignant warts.

b. Adenocarcinomata.

c. Epithelial hypertrophy in ulcers, and sinuses.

3. Late cancers.

a. Spino-celled cancers.

b. Cubo-celled cancers.

c. Baso-celled cancers.

Inasmuch as this book is primarily intended for the clinician, it has seemed to the author to be best to give a clinical, rather than a pathological, nomenclature, and he has adopted the following:

1. Benign epithelial tumors.

a. Keratomata.

b. Mixed-celled epithelial warts.

c. Spinous-celled epithelial warts.

d. Baso-celled epithelial tumors.

Nevoid.

Multiple benign.

2. Malignant epithelial warts.

a. Spino-celled.

b. Baso-celled.

3. Baso-celled carcinomata.

a. Flat rodent ulcer.

b. Button-like or nodular carcinoma.

c. Rolled-edge carcinoma.

d. Depressed scar-like carcinoma.

e. Morphea-like carcinoma.

f. Fungating carcinoma.

g. Ulcerative carcinoma.

4. Cubo-celled carcinomata.

a. Ulcerative carcinoma.

b. Fungating carcinoma.

5. Spino-celled carcinomata.

a. Ulcerative carcinoma.

b. Fungating carcinoma.

6. Tumors of hair follicles.

a. Benign (multiple benign cystic epithelioma of Jarisch).

b. Carcinoma.

7. Tumors of sweat glands.

a. Adenoma.

b. Carcinoma.

8. Tumors of sweat ducts.

a. Adenoma.

b. Syringocystadenoma.

9. Tumors of sebaceous glands.

a. Adenoma sebaceum.

b. Adenoma.

c. Adenocarcinoma.

10. Nevocarcinomata (and multiple pigmented carcinomata).

11. Paget's disease.

12. Carcinomata by extension.

13. Metastatic carcinomata.

14. Carcinomata en cuirasse.

15. Endotheliomata capitis.

Some authors, notably Adami* and Hertzler,* object to Krompecher's differentiation of skin carcinomata into prickle and basal cellular types, pointing out that the prickle cells are simply a differentiation of the basal cells, and are not of a different origin. But to the author this classification seems justified, for the two types of tumor run absolutely different clinical courses-courses even more distinct than the histological pictures. The basocellular tumor is usually of slow, or of comparatively slow, growth, and practically never metastasizes, thus differing markedly from the spinous-celled tumors, which grow rapidly, and usually form metastases. Krompecher also recognizes a basocellular glandular tumor, a neoplasm less malignant than the type of adenocarcinoma, in which the cell type is that of the superficial epithelial lining of the ducts. Bloodgood is inclined to agree with Krompecher in this assertion.