84 



A comparison of tick conditions in the two regions studied illustrates 

 the great diversity of the problems to be faced in the work of eradica- 

 tion. Points that it is particularly desirable to investigate are the 

 factors governing the periodical abundance of ticks, the relation of 

 rabbits to the occurrence of the fever, tick conditions in regions where 

 ground squirrels occur, the host-relationships of the tick, and the 

 factors governing the occurrence of the fever in Carbon County, where 

 cases of fever occur almost every year. 



WoLBACH (S. B.). Rocky Mountain Spotted Fever, Pathology and 

 Etiology ; Progress. — 3rd Bienn. Rept. Montana State Bd. Entom., 

 1917-1918; Helena, 15th December 1918, pp. 55-60. [Received 

 7th March 1919.] 



The results of earlier investigations on the parasite of Rocky 

 Mountain spotted fever have pre-^iously been published [see this 

 Review, Ser. B, v, p. 80]. The further study of the disease in both 

 man and animals has clearly proved it to be a specific infectious 

 endangitis of the peripheral blood-vessels ; the disease being exactly 

 duplicated in man and animals. 



The parasite as found in sections of ticks exhibits the following 

 forms : (1) a lanceolate paired form similar to those seen in mammals ; 

 (2) a smaller, more slender rod-shaped form ; (3) a minute, oval 

 coccoid form just within the limits of vision. Only the first of these 

 can be found in ticks that have been kept for several months. In 

 spite of a most extensive series of experiments this parasite has not 

 yet been cultivated, but its relationship to Rocky Mountain spotted 

 fever must be accepted as proved in view of its constant occurrence 

 in the specific lesions in man and laboratory animals and because 

 it has been proved to be inseparable from infective ticks. Efforts 

 were made to determine the duration of infectivity of the tick. Ticks 

 infected as nymphs proved infective after 17 months, which is 

 approximately the maximum life period of an unfed adult. The 

 infectivity of eggs from infected females has been confirmed. Experi- 

 ments with rabbits indicate that there is no transmission of immunity 

 to the young of immune parents. The behaviour of the virus in rabbits 

 requires further study, as the strain in them could not be maintained 

 indefinitely, there being a gradual decline in infectivity with repeated 

 passage. It does not seem probable, in the light of recent experiments, 

 that a highly potent immune serum can be obtained from the smaller 

 laboratorv animals. 



Gros (H.)- a propos d'Anophehs chaudoyei. — Bull. Soc. Path. Exot.^ 

 Paris, xii, no. 2, 12th February 1919, pp. 53-54. 



It is pointed out that recent notes on Anopheles chaudoyei [see 

 this Revieiv, Ser B, vi, pp. 141, 201] suggest that this species is peculiar 

 to the oases of Algeria and Tunisia. The author in 1904 recorded 

 the existence in the valley of the Sebaou of three species of Anopheles, 

 one of which was A. chaudoyei, and it is probable that this species 

 occurs over a wide area in Algeria and Tunisia and is not confined to 

 the Sahara. 



