LUNGS. 89 
with new cells remains permanent. Such a case runs a very chronic 
course and is called a persisting broncho-pneumonia. 
What are the changes in secondary and complicating pneumonia ? 
The inflammation usually occurs with lesions of the brain and spinal 
cord, pyzemia, continued fevers, surgical operations and with some of 
the infectious diseases. The lung may be congested and mottled with 
irregular patches of red and gray hepatization and the air spaces filled 
with fibrin and pus. Or the lesion may follow the same type of in- 
flammation as a broncho-pneumonia. 
What are the lesions in a case of pneumonia of heart disease ? 
The capillaries in the walls of the air spaces are dilated and appear 
to be increased in length so that they are tortuous in their course and 
often project into the air spaces. The walls of the air spaces are 
thickened. There is a formation of black or brown pigment granules, 
which may be deposited in the walls of, or in the new cells formed in, 
the air spaces. In these spaces, also, numbers of leucocytes are usually 
seen. 
What are the changes in an interstitial pneumonia ? 
It usually follows a broncho-pneumonia or a chronic bronchitis, or 
arises from the inhalation of dust. There is an increase of connective 
tissue between the lobules and air spaces which may compress or even 
obliterate these spaces. The walls of the bronchi are the seat of a 
chronic catarrhal inflammation. 
Describe tubercular pneumonia. 
The classification of the forms of tubercular pneumonia seems best 
made upon the basis of their clinical history. The cases may be 
divided into acute, sub-acute and chronic miliary tuberculosis, acute 
and chronic phthisis. 
What are the lesions of acute miliary tuberculosis ? 
In this form, which is generally accompanied by a general tuber- 
cular infection, there is a formation of miliary tubercles scattered 
irregularly throughout the lung tissue. These tubercles may grow in 
the walls of the air spaces or in the walls of the bronchi, or in the 
pleura. They are composed of tubercle tissue and vary widely in 
appearance. They may have become entirely cheesy, or only cheesy 
at the centre, or may not have degenerated at all. Tubercle bacilli 
can usually be demonstrated in them. There is a catarrhal bronchitis 
present, and the air spaces near the affected parts may contain epithe- 
lium, pus and fibrin. 
