The Animal Parasites of Man. Max Braun

the identity of the organism of yaws and also of differentiating between the causative agents of yaws and syphilis. Both monkeys and the human subject have been experimentally inoculated with yaws material and have developed the disease.

      In an early experiment, negroes were inoculated with the secretion from lesions of yaws. All of them developed the disease, nodules appearing, chiefly at the seat of inoculation, in from twelve to twenty days, followed by the usual eruption. Similar results were obtained with thirty-two Chinese prisoners, who were inoculated with yaws, twenty-eight becoming infected.

      A naturally infected yaws patient when inoculated with syphilis, contracted that infection, thus showing that yaws does not confer immunity to syphilis. This has also been observed naturally, when yaws patients have contracted syphilis.

      Experiments with monkeys have been successfully performed. The incubation period varies from sixteen to ninety-two days. Lesions appear first at the seat of inoculation, and in some monkeys the eruption is localized to this spot, though the infection is general, T. pertenue occurring in the spleen, lymphatics, etc. Monkeys inoculated with splenic blood of a yaws patient, and also sometimes with blood from the general circulation, have become infected.

      Castellani and others have shown that monkeys successfully inoculated with syphilis do not become immune to yaws, and vice-versâ.

      Craig and Ashburn, using the monkey Cynomolgus philippinensis, found these animals susceptible to yaws but not to syphilis.

      The ulcerated lesions of frambœsia are rapidly invaded by numerous bacteria as well as by different spirochætes, of which Castellani has described three distinct species. One is identical with Spirochæta refringens, Schaudinn, the other two are thin and delicate. One, S. obtusa, has blunt ends; the other S. acuminata, has pointed ends. T. pertenue is also present.

      The reasons for considering T. pertenue to be the specific cause of frambœsia are:—

      (1) T. pertenue is the only organism present in non-ulcerated papules, in the spleen and in the lymphatics of yaws patients, or of monkeys artificially infected with the disease. By no method has any other organism been obtained.

      (2) Extract of frambœsia material, free from all organisms other than T. pertenue, reproduces the disease if inoculated.

      (3) Extract of frambœsia material deprived by filtration of T. pertenue is no longer infective on inoculation.

      The method of infection is contaminative, by direct contact. Women in Ceylon are frequently infected by their children. Any slight skin abrasion is sufficient to admit the parasite. In some cases, insects may carry the disease from person to person, and even in hospitals, when dressings are removed, it has been noticed that flies greedily suck the secretion from the ulcers. T. pertenue has been recovered from flies that have fed on yaws, and monkeys have contracted the disease when flies were placed and retained on them for a short time, after the insects had fed on yaws material.

      Cultivation.—T. pertenue has been cultivated by Noguchi, who finds three types of parasites in his cultures, as before mentioned. Its multiplication is by longitudinal division.

      Noguchi169 (1912), has cultivated species of Treponema from the human mouth, e.g., T. macrodentium, T. microdentium and T. mucosum, the latter from pyorrhea alveolaris. These parasites in the past may have been confused under the name Spirochæta dentium.

      Class III. SPOROZOA, Leuckart, 1879.

The third group of the Protozoa consists entirely of parasitic organisms forming the class known as the Sporozoa or spore-producing animals. The members of this class are characterized by possessing very great powers of multiplication, coupled with a capacity for producing forms that serve for the transference of the organisms to other hosts. These reproductive bodies, whether for increase of numbers within one host or for transmission to another host, are called spores. But, strictly, the term spore should be used only in the latter connection, when a protective or resistant coat known as a sporocyst envelops the body of the spore.

      The Sporozoa are widely distributed, occurring in various tissues and organs of Annelids, Molluscs, Arthropods, and Vertebrates. Their food, which is fluid, is absorbed osmotically. The life-cycle of a Sporozoön may be completed within one host or may be distributed between two different hosts.

      The Sporozoa were divided by Schaudinn into two groups or sub-classes, called (1) the Telosporidia, and (2) the Neosporidia.

      The Telosporidia are Sporozoa in which the reproductive phase of the parasites is distinct from the growing or trophic phase, and follows after it. The Neosporidia include Sporozoa in which growth and spore-formation go on simultaneously. This classification is not final, for certain exceptions and difficulties are already known with regard to it. It is possible that the class Sporozoa is not a natural entity, but should be replaced by two classes of equal rank, corresponding in most respects with the Telosporidia and Neosporidia.

      The Telosporidia comprise the Gregarinida, the Coccidiidea, and the Hæmosporidia. Doflein combines the two latter orders into one known as the Coccidiomorpha.

      The Neosporidia comprise the Myxosporidia, the Microsporidia, the Actinomyxidia, the Sarcosporidia, and the Haplosporidia. Doflein combines the first three orders into one, the Cnidosporidia.

      Sub-Class. TELOSPORIDIA, Schaudinn.

      Sporozoa in which the reproductive phases follow completion of growth.

      Order. Gregarinida, Aimé Schneider emend. Doflein.