189 



Austen (E. E.) & Hegh (E.). Tsetse-flies. Their Characteristics, 

 Distribution and Bionomics with some Account of possible Methods 

 for their Control. — London, Imp. Bur. Ent., 1922, Roy. 8vo, 

 ix + 188 pp., 5 plates, 19 figs., Price 7s. 6d. 



Since the publication of Hegh's account of the subject [R.A.E., 

 B, iv, 36], a very large amount of work, especially in the British 

 Colonies and Protectorates, has been done on the biology of the various 

 species of Glossina. The information thus acquired is scattered among 

 a large number of scientific and medical journals, and the difficulty that 

 would face an investigator who wished to collect it as a preliminary to 

 further work would be great — in Tropical Africa almost insuperable. 



These consideraticns have rendered necessary the preparation 

 of the volume under review, which, as the very extensive bibliography 

 of publications consulted indicates, contains the information required to 

 bring Hegh's account up to date, and which furnishes a thoroughly 

 comprehensive resume of the present knowledge of the subject. 



WoLBACH (S. B.), Todd (J. L.) & Palfrey (F. W.). The Etiology 

 and Pathology of Typhus: Being the Main Report of the Typhus 

 Research Commission of the League of Red Cross Societies to 

 Poland. — Cambridge, Mass. (League of Red Cross Societies), 

 Harvard Univ. Press, 1922, Imp. 8vo, x + 222 pp., 13 figs., 

 34 plates. [Price 35s.] 



As a main result of their investigations [cf. R.A.E., B, ix, 137], 

 the Commission reached the conclusion that the specific cause of 

 typhus is Rickettsia prowazeki. So far as the insect host was concerned 

 the experiments were made with lice that were certainly free from 

 Rickettsia or the virus of any disease. They were fed on cases of 

 clinically well-established typhus, and emulsions of their viscera were 

 then injected into guinea-pigs. The fact that these lice acquired only 

 R. prowazeki in the way of demonstrable micro-organisms from the 

 typhus patients is in itself strong evidence for the relationship of 

 R. prowazeki to typhus ; but the experiments in inoculation in guinea- 

 pigs appear to prove conclusively that the virus of typhus is not 

 separable in the louse from R. provoazeki, and this the authors consider 

 to be the most important part of their evidence. It was supported, 

 also, by a large number of histological observations on the human 

 subject, the presence of bodies indistinguishable from R. prowazeki 

 being demonstrated with great regularity in the lesions of typhus 

 in man. 



The lice do not invariably become infective when fed upon typhus 

 patients ; and it would appear that the mechanism of typhus trans- 

 mission is an imperfect one in more than one respect, for R. prowazeki 

 eventually destroys the louse, which is an unusual effect of a parasite 

 upon its intermediate host. 



The mode of conveyance of the virus from the louse to the human 

 subject was not demonstrated. It is certain that R. prowazeki escapes 

 from the alimentary tract with the faeces and may, therefore, be 

 introduced by scratching or by the mouthparts of the lice after becoming 

 soiled with faeces. In no instance were Rickettsia observed in the 

 salivary glands or oesophagus of the lice. 



An incident of considerable interest occurred during the research, 

 when one member of the Commission was taken ill with trench fever, 

 the lice that were fed on him thereafter becoming heavily infected 



(7673) Wt. P6/200 1500 10,22 Harrow G 75,3. Q 



