. Microbes & toxins. Bacteriology; Toxins; Antitoxins. APPLICATIONS OF BACTERIOLOGY 253. Fig. 71.—Agglutination of the typhoid bacillus by the serum of a typhoid patient: b, clump of bacilli : , blood corpuscles left in the serum. throughout the liquid; the suspension is "; If a trace of serum is added from an animal prepared by injections of typhoid bacilli or from a patient suffering from typhoid fever, the bacilli lose their motility and collect into masses: they are said to become agglutinated by the serum. If the serum is added to a broth culture floccules ca
. Microbes & toxins. Bacteriology; Toxins; Antitoxins. APPLICATIONS OF BACTERIOLOGY 253. Fig. 71.—Agglutination of the typhoid bacillus by the serum of a typhoid patient: b, clump of bacilli : , blood corpuscles left in the serum. throughout the liquid; the suspension is "; If a trace of serum is added from an animal prepared by injections of typhoid bacilli or from a patient suffering from typhoid fever, the bacilli lose their motility and collect into masses: they are said to become agglutinated by the serum. If the serum is added to a broth culture floccules can be seen with the naked eye forming and sinking to the bottom of the tube; agglutination is also a sedimentation. Nor- mal serum never possesses this property, certainly never to the same degree. The agglutinating power may be measured by try- ing the effect on a suspension of the bacilli of various dilutions of the serum : one may say that such and such a serum agglutinates at i in 50, i in 100, i in 1000. . The reaction is capable of two applications. With a bacillus definitely known as a genuine B. typhosus, one can say that the serum which agglutinates it is an antityphoid serum. If, on the other hand, with such a definitely known serum we find a bacillus agglutinated, we may say that it is a true B. typhosus. Agglutination may be used to diagnose now the bacillus, now the disease. The agglutinating power depends on an antibody named the agglutinin. This substance keeps much longer than the time required for its carriage to long distances for examination, when this is necessary. Dead bacteria also agglutinate, so that the method may be employed even without living cultures. Seroagglutination is therefore the simplest and most convenient of the biological methods. In performing the test it is necessary to avoid certain sources of error, among others the existence of bacterial strains. Please note that these images are extracted from scanned page images that may have been
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