Page:Tropical Diseases.djvu/851

Rh lopsis buski, Schistosomum japonicum, and also P. westermani. The establishment of these exotic species will depend, among other things, on their finding appropriate intermediary hosts. Symptoms.— The subjects of endemic hæmoptysis have a chronic cough, which is usually most urgent in the morning on rising. The fits of coughing eventuate in the expulsion of a peculiar rusty-brown, pneumonic-like sputum. This sputum can be produced at will almost at any time, and often in considerable quantity. In addition to the chronic cough and the tenacious rusty expectoration referred to, the patient is liable to irregular attacks of hæmoptysis. Though usually induced by violent exertion, occasionally such attacks come on without apparent cause. The hæmoptysis may be trifling; on the other hand, it may be so profuse as to threaten life— at all events, to cause intense anæmia.

The sputum.— On placing a minute portion of the viscid, pneumonic-like sputum under the microscope, its peculiar colour is found to be due partly to red blood-corpuscles, partly to a crowd of dark- brown, thick-shelled, operculated ova (Fig. 161). These ova vary a good deal in size and shape; they are all distinctly oval, have a yellow, smooth, double-outlined shell, and measure from 80 to 100 μ. in length by 40 to 60 μ in breadth. If the sputum be shaken up in water, and the water be renewed from time to time, in the course of a month or six weeks— longer or shorter according to temperature a ciliated miracidium is developed in each ovum. When the ovum is mature, on placing it on a slide and exercising slight pressure on the cover-glass the operculum will be forced back, and the miracidium will immediately emerge and begin to swim about and gyrate in the water.

Pathological anatomy.— On making a section of the lungs in this disease, a larger or smaller number of what are known as " burrows " are discovered scattered about this organ, particularly towards the periphery. These burrows consist of areas, somewhat larger than a filbert, of infiltrated lung tissue in