58 CHOLERA 



outburst at Hamburg belongs to this period. In 1902 cholera for the 

 sixth time became pandemic. It was disseminated by 400,000 pilgrims 

 gathered together at Mecca. Since that time and up to the present it 

 has been found in various parts of Europe and has repeatedly reached 

 our own shores, but has not been permitted to gain a foothold. 



In all these excursions, among all kinds and conditions of men, 

 in every degree of civilization, in the tropics and amid the snow and 

 ice of northern Russia, in the thronged city and in the emigrant's 

 wagon, with high and low, slave and master, wherever it has traveled, 

 cholera has maintained its individuality and has shown no modification 

 in manner of attack or variation in the symptoms induced in its victims. 

 Its vehicle of transport has been man's body and it has followed the 

 lines of human travel, on foot, on horse or camel, by stage or ox 

 team, by steam, on land and sea. The sick and dying have scattered 

 its progeny around the world. The science of preventive medicine is 

 the only detective who can trace this criminal, the only officer who 

 can arrest it and the only executioner who may finally remove it for 

 all time from the earth. 



The Bacillus. In 1883 the German government sent a commission 

 with the distinguished bacteriologist, Robert Koch, at its head, first 

 to Egypt and then to India to ascertain the cause of this disease. Many 

 months were spent in the study of the discharges of the sick, the post- 

 mortem examination of the dead and the investigation of the food 

 and drinking-water of the infected. The result was the discovery of 

 the infective agent, and this has placed in man's hands the possibility 

 of completely eradicating this disease. The bacillus is a slightly curved 

 rod, averaging about 1.5 micron in length and one-third this in breadth, 

 but with many variations. Frequently, many individuals are attached, 

 end to end, forming something like the letter S. It is known as the 

 comma bacillus or the cholera vibrio. It is distinguished from similar 

 vibrios by having a single flagellum or whip at one end. Its rapid 

 motility in suspension is due to this whip. Sometimes the form is 

 ovoid, often much longer and shows a long whip. It is easily recog- 

 nized in the stools by an expert and the diagnosis in suspected cases is 

 easy and certain. It takes the ordinary basic stains easily and deeply, 

 but in order to stain the whip a mordant dye is desirable. It grows 



