﻿108 ASHBURX AND CRAIG. 



tion does not occur more rapidly nor is it more marked in dengue than 

 in other acute, febrile conditions. Tacuolation is common both in fresh 

 and stained specimens of blood, and in many instances the shape and 

 appearance of the vacuoles is very suggestive of a parasitic invasion of 

 the red cell; artefacts, due to degeneration of the protoplasm and clear 

 areas due to retraction of the haemoglobin, are common, especially in 

 poorly prepared smears and are well calculated to lead to error because 

 of their resemblance to bacterial or protozoal organisms. "We have not ob- 

 served that the appearance of the vacuoles occurring in the red corpuscles 

 in dengue differs from that seen in many other febrile conditions, 

 but it is certainly true that they frequently present an appearance very 

 suggestive of amoeboid motion without change of position ; the progres- 

 sive motion referred to by some writers which we have observed in the case 

 of rod-shaped artefacts, is probably due to protoplasmic currents within 

 the degenerating red cell. 



It is not uncommon to observe in the blood of dengue, as well as in 

 that of other febrile conditions, cocci or bacilli, either free in the blood 

 plasma or attached to the red blood corpuscles; in the vast majority of 

 instances these bacteria are due to external contamination and have no 

 relation to the disease in which they are observed ; when they are attached 

 to the red blood cell and still possess some motility their resemblance to a 

 parasite is often striking, but it is possible by gentle pressure to dislodge 

 them and thus demonstrate their real nature. 



We have not observed the presence of normoblasts or megaloblasts in 

 the blood in dengue, and their absence, especially of normoblasts, indicates 

 that anaemia even of a mild type, is not present. 



The staining reactions of the red corpuscles in dengue do not differ 

 from those present in health. Polyehromatophilia or basophilia we 

 have not observed, but in poorly prepared specimens the staining may be 

 irregular, suggesting granular degeneration. 



From our observations we conchule that the morphology of the red 

 cell in dengue shows no diagnostic changes. 



(c) Tlie leucocytes. — Xumber: One of the most important blood 

 changes in this disease is the presence in alm-ost every case of a marked 

 leucojjenia. From our observations we are convinced that the leucopenia 

 of dengue is almost constant throughout the attack, and that it is of 

 considerable diagnostic importance. We have made leucocyte counts in 

 a large number of eases and have invariably found a marked reduction in 

 the total number with, as will be seen later, a quite characteristic change 

 in the relative proportion of the various forms. The lowest leucocyte 

 count was 1,200 per cubic millimeter, the highest 4,860, the average, 3,800. 

 Carpenter and Sutton (22) found a constant leucopenia, the lowest 

 count being 1,8GG, the highest 5,866, the average about 3,500, per cubic 

 millimeter. Stitt (20) states that a leucopenia is always present, and his 

 counts varied from 1,450 to 5,280 per cubic millimeter. We have found 



