ENTOMOLOGY

SANITARY ENTOMOLOGYNo definite organism has been finally fixed on as the cause of typhusfever although several have been described. Plotz (1914) and others,with excellent reasons, regard IJacillus typhi l13Jtmthematici as the cause.Bodies called Rickettsia prowazeki DIl. Rocha-Lima (1916), are describedby Da Rocha-Lima, Noeller (1916), and others, as the causative organism,and it is claimed that they undergo multiplication in the cells of themidgut of infested lice. Whether Rickettsia is the cause of the disease ora product of the contagium'is still uncertain. Stempell (1916) describesa Protozoan, StricTceria jilrgensi, which he suspects to be the cause oftyphus, and claims that it undergoes part of its development in the intestinesof Pediculus corporis, and i~ sometimes transmitted to man inlarge numbers. Rabinowitch (1914-1916) regards Diplobacillus exanthematicusas the cause; Penfold (1916) describes a Micrococcus; Proescher(1915) describes minute Diplococci and Diplobacilli as present in theendothelial cells of the human subject. Finally Futaki (1917) hasdescribed Spiroschaudirttnia exanthematotyphi from tbe liver and urine ofpatients dying of typhus and has found the same organism in lice. Brumpt(1918) discu!!ses Rickettsia prowazeki Da Rocha-Lima, the so-calledcause of typhus fever, and claims that it is a coccobacillus and that hefound it in 73.6 per cent of the lice (Pediculus corporis) from healthyprisoners in France. He found that these lice infected with this organismremained infective all their lives and therefore c~mcludes that Rickettsiacannot be the cause of typhus fever, even though it may be transmitted bythe lice to men and again taken up by them. In experiments on himselfwith infected lice he did not produce any infection. Brumpt perhapsfound the Rickettsia pediculi which is associated with normal lice.TRENCH FEVER.-This disease has only recently been recognized,having passed even in the early days of the war under the initials P. U. 0.,or pyrexia of unknown origin. Many of the greatest investigators in thevarious armies concentrated attention on this baffling disease of thetrenches which stood among the highest of the disabling diseases of theWestern front. The :first records of the connection of the louse werecontained in statements of Davies and Weldon (1917, 1918) that one ofthem had produced the disease in himself by permittin'g infected lice(Pediculus corporis) to bite him. The incubation period was H! days.Early in 1918 two separate committees, the British under Sir DavidBruce and Major W. Byam, and the American under Dr. R. P. Strong,succeeded in Iproving louse transmission. The English committee (Bruce1918) in an experiment in which lice were crushed on a scarified areaof skin of volunteer patients incubated the disease in eight and ten days.In experiments with the feces of lice fed on trench fever patients, a smallamount of dried excreta rubbed on a scarified area of skin, incubated thedisease in three men on the sixth, ,seventh and eighth days. Blood from