Further, according to Marchoux and Couvy, infection takes place without the emission of the coxal fluid and indeed, soiling of the host by the coxal fluid diluting the excrement is exceptional. All of the organs of the Argasid are invaded by the parasites, but they pass from the cœlom into the acini of the salivary glands and collect in its efferent canal. The saliva serves as the vehicle of infection. Thus, the question of the life cycle of _Spirochæta gallinarum_, and of spirochætes in general, is an open one. It should be noted that _Argas persicus_, the carrier of _Spirochæta gallinarum_, is a common pest of poultry in the southwestern United States. Though the disease has not been reported from this country, conditions are such that if accidentally introduced, it might do great damage. OTHER SPIROCHÆTE DISEASES OF ANIMALS--About a score of other blood inhabiting spirochætes have been reported as occurring in mammals, but little is known concerning their life-histories. One of the most important is _Spirochæta theileri_ which produces a spirochætosis of cattle in the Transvaal. Theiler has determined that it is transmitted by an Ixodid tick, _Margaropus decoloratus_. TYPHUS FEVER AND PEDICULIDÆ Typhus is an acute, and continued fever, formerly epidemically prevalent in camps, hospitals, jails, and similar places where persons were crowded together under insanitary conditions. It is accompanied by a characteristic rash, which gives the disease the common name of "spotted" or "lenticular" fever. The causative organism is unknown. Typhus fever has not generally been supposed to occur in the United States, but there have been a few outbreaks and sporadic cases recognized. According to Anderson and Goldberger (1912_a_), it has been a subject of speculation among health authorities why, in spite of the arrival of occasional cases in this country and of many persons from endemic foci of the disease, typhus fever apparently does not gain a foothold in the United States. These same workers showed that the so-called Brill's disease, studied especially in New York City, is identical with the typhus fever of Mexico and of Europe. The conditions under which the disease occurs and under which it spreads most rapidly are such as to suggest that it is carried by some parasitic insect. On epidemiological grounds the insects most open to suspicion are the lice, bed-bugs and fleas. In 1909, Nicolle, Comte and Conseil, succeeded in transmitting typhus fever from infected to healthy monkeys by means of the body louse (_Pediculus corporis_). Independently of this work, Anderson and Goldberger had undertaken work along this line in Mexico, and in 1910 reported two attempts to transmit the disease to monkeys by means of body lice. The first experiment resulted negatively, but the second resulted in a slight rise in temperature, and in view of later results it seems that this was due to infection with typhus.