TYPHOID FEVER—ABDOMINAL TYPHUS It is met with in childhood about as frequently as at other periods of life.
With regard to the mode of transmission, it was formerly thought to be really contagious, hut this of such slight degree that nobody cared particularly to isolate the patients. Certain observations, how ever, communicated especially by Dr. Robert Koch from his careful study of an epidemic, warn us to have more regard for the contagious factor—not only to disinfect, and remove dejecta, urine and sputa, which for some tiine have been considered as the most important sources of the disease, but also to isolate the patient. Even the early investi gators warned against infection through the water used for drinking, culinary purposes, or bathing (a sad example of which Prague has for years been furnishing), yet as Koch points out, this is to be less regarded than those mild cases which clinically are hardly noticed; healthy indi viduals whose evacuations contain typhoid bacilli, and must he appre ciated as disseminators of the disease. We should not however follow him in this curt disregard for hitherto prevailing views, although we may infer from his observations and from his protective measures thus successfully established that besides the hitherto combated sources of infection there are others that should be considered.
Where typhoid fever is endemic we observe often enough that in fants, even those that are nourished exclusively on their mothers' or nurses' breasts, become affected and infect their nurse. In such cases the infection must have taken place through other than the usual chan nels, and the water used for bathing has been suspected. Cow's milk too, may be instrumental in spreading the disease, infected by water used for the purpose of diluting the milk, or by flies carrying the bacilli, etc. Cases of intrauterine infection, generally resulting in death and 434 expulsion of the fwtus, have rather a casuistic interest. Transmission through suction is asserted by some, denied by others, and as a rule is difficult to prove, in that an affected nurse can infect the baby in many ways. On the other hand, there are cases in which nurses suffering from
typhoid fever of moderate severity have taken certain precautions and have attended the infants during the whole course of the fever withoLt infecting them,—an experiment too daring to be imitated.
The cause of the disease is the typhoid bacillus, described by Eberth and first cultivated by Gaffky,—a cylindrical bacillus with rounded ends, and provided with a chaplet of cilia, presents lively transverse and longitudinal movements. It easily takes the aniline dyes and rapidly gives them up again, grows on the usual culture media, is facul tative anaerobic, and ceases to grow at a temperature above 46° C. (115°F.). The appearance of the cultures is not very characteristic, that on potatoes being the most striking one, a moist, lustrous, mucous coating, looking like parchment. A knowledge of the appearance of bouillon cultures is important, since these show a diffuse turbidity within 12 to 24 hours, but, with transmitted light, exhibit darker stripes, resembling the vein-like markings on marble. In appropriate culture media the typhoid bacillus does not produce gas nor ferment sugar, nor cause indol formation, nor does it coagulate milk.
The great powers of resistance and endurance of the bacilli assumed on the strength of experiments made by Janowski and others, by virtue of which they are able to live in the water and in the ground for a long period and even resist freezing, arc controverted by Koch on the strength of his own investigation. He admits, however, that they will withstand desiccation, which does not hurt their vitality. A consideration of the clinical features of the disease and the post-mortem appearances points to the production of a soluble poison by the bacilli, but the production of such a poison has as yet been impossible.