224 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



the primary reservoir of verruga, certain of the native rats and mice 

 or other small rodents are most strongly indicated. The rice rats, 

 comprising many species of Oryzomys, are common throughout South 

 America and well represented in the whole coast region of Peru; they 

 are probably not concerned in verruga transmission at present, though 

 there is a possibility that they might become so under extraordinary 

 conditions. The Octodontidce and especially the Cricetince, relatives 

 of the pocket mice and grasshopper mice, are very abundant in forms in 

 the Andean region, and it seems most probable that among them is 

 to be found the primary reservoir of verruga. 



Note. — Since writing the above, two important points with refer- 

 ence to verruga have come to light. The Magdalena quebrada, in the 

 department of Cajamarca, has very recently been found to be a 

 strong focus of verruga. Various other localities that have been 

 discovered since the publication of Dr. Odriozola's monograph show 

 verruga to be present at this date in the departments of Lima, Ancachs, 

 Libertad, Lambayeque, Cajamarca, probably the southeastern corner 

 of Piura, and perhaps the southwestern part of Amazonas, extending 

 the known present range northward to 6° south latitude. 



The other point is that Drs. Julio C. Gastiaburu and Raul Rebagliati, 

 of the Lima Institute of Hygiene, have recently found in the eruption 

 of verruga and in the liver of verruga patients in the eruptive phase 

 certain bodies, at times endoglobular, in leucocytes and certain cells, 

 at other times free, which by their staining reaction and morphological 

 aspect seem to them to resemble organisms of the genus Leishmannia. 

 It is possible that these are the ookinete stage of the pathogenic organ- 

 ism before it has given off the numerous ultramicroscopic infective 

 sporozoite-stage organisms. 



The same authors have found also certain new endoglobular bodies 

 in successive degrees of segmentation which they consider to be rem- 

 nants of nuclear disorganization of the erythrocyte, and which suggest 

 to them that Barton's a:-bodies may be chromatin filaments segregated 

 from the nuclei of the erythroblasts. It is probable that these endo- 

 globular a;-bodies of the erythrocytes, including Barton's rc-bodies, 

 are the results of the disorganization of the erythrocyte by the invisible 

 non-infective trophozoite stage of the pathogenic organism, during 

 its development to the merozoite stage. The merozoites evidently 

 do not attack new erythrocytes, but as soon as produced they congre- 

 gate in the subcutaneous tissues. Here some of them develop to male 

 and female gametocytes, from the conjugation of whose elements the 

 ookinete is formed. The plan of life-cycle and reproductive habit 

 here suggested for the pathogenic organisms of both verruga and 

 Rocky Mountain spotted-fever are, of course, purely hypothetical. 



