of the Sputum in Phthisis. 181 



but little doubt that under the designation of Phthisis, at least 

 several distinct maladies are commonly included; and some of 

 these even tend to the destruction of the lung tissue in a manner 

 scarcely to be distinguished from the process of ulceration occurring 

 in connection with softened tubercle. Nevertheless, the detection 

 of this tissue in the expectoration is perhaps the clearest diagnostic 

 mark of phthisis that the sputa can afibrd. Professor Bennett's 

 case of the discovery of elastic lung tissue under the microscope, 

 prior to the development of true phthisical symptoms, appears to 

 have been followed by few, if any, other good examples of the kind. 

 There is, however, great promise that with improved methods of 

 examination, as, for instance, the process recommended and so suc- 

 cessfully practised by Dr. Fenwick,* much may yet be done to 

 elucidate this important point. It usually happens that at the 

 time we are able to trace such anatomical elements in the sputa, 

 the disease has sufficiently manifested its real nature by other 

 attending signs and symptoms. It seems to be generally admitted 

 that the characters of the elastic tissue of the air-cells are so dis- 

 tinctive, that there is little likelihood of anything else being mistaken 

 for it, and it is quite true that an experienced microscopist may not 

 confound other fibrous tissues with it. But the tyro must be made 

 aware that many things of an extraneous nature will be sure to 

 deceive him, unless he makes himself acquainted with the minute 

 anatomy of the air-cells, more esj)ecially with the microscopical 

 appearance and mode of distribution of their supporting fibrous tissue. 



The accompanying Figs. 1 and 2, Plate LXXVIII., are selected 

 for the guidance of those who may not be familiar with the structure 

 of the air-cells. The first represents a portion of inflated and dried 

 lung, showing the comparative size and general disposition of the 

 air-cells, as seen with a half-inch power. The second was drawn 

 from a small portion of recent lung divested of its epithelium, and 

 treated with acetic acid to render the investing tissues more trans- 

 parent, and thus to display the fibrous basis more distinctly (mag- 

 nified about 300 diameters). 



Should tubercular matter be deposited in the cells themselves, 

 or between the layers of the basement membrane in contact with 

 the fibrous tissue, the irritation thus induced will sooner or later 

 lead to inflammatory action and the development of its products, 

 lymph and pus. With the central softening and ultimate breaking 

 down of the tubercle, an ulcerative process is set up, by which frag- 

 ments of pulmonary tissue become detached and are expectorated 

 with the surrounding pus and mucus from the bronchial membrane. 

 Such fragments are therefore commonly to be found in the sputa 

 of persons affected with phthisis, and the credit of having first 

 discovered them by the aid of the microscope belongs to Professor 



* See ' Lancet,' December 5th, 1868. 



o 2 



