SYMPTOMS AND BLOOD-CHANGES 349 



normally we find an average of 8,000 leukocytes (in children somewhat more 

 9,000 to 10,000) in a cubic millimeter of the blood taken from the veins, i. e.' 

 one white cell to 600 erythrocytes, the number of leukocytes may so increase 

 in leukemia that the proportion is 1 to 50, 1 to 10, or 1 to 2. In fact, the red 

 and white blood-corpuscles may even be present in similar amounts in the 

 blood. The count of white blood-corpuscles shows 100,000 and even 600,000 

 and more, to the cubic millimeter. 



In some cases of leukemia, no noteworthy change in the erythrocytes, either 

 in number or appearance, occurs; as a rule, however, they are decreased in 

 numbers to about one-half of the normal or even less, just as in severe anemias. 

 In general the decrease of the erythrocytes is in proportion to the increase 

 in the number of white blood-corpuscles. But the numerical relation of the 

 erythrocytes in leukemia is a secondary consideration, and the diagnosis of 

 the affection depends primarily upon the white blood-corpuscles. There are 

 eases of sim.ple anemia in which the number of red blood-corpuscles is mark- 

 edly diminished, but the production of white has remained normal ; then the 

 proportion of the white to the red cells may become 1 to 25, etc., without 

 leukemia being present. For example, in pernicious anemia, with a diminu- 

 tion of the erythrocytes to 250,000 to the cubic millimeter, and a normal con- 

 dition of the white blood cells (8,000), the proportion would be about 1 to 

 30 and still no leukemia would be present. Leukemia is, however, to be as- 

 sumed under all circumstances if the proportion falls below 1 to 20, because 

 these figures can only occur when, besides the decrease in the number of the 

 red blood-corpuscles as a result of anemia (even in the most excessive diminu- 

 tion of the same that has been observed up to the present in cases of per- 

 nicious anemia), the number of leukocytes is absolutely increased at the 

 same time. 



Besides the diminution in the number of red blood-corpuscles, the blood 

 also contains, as a rule, numerous nucleated red ilood-corpuscles in the form 

 of normoblasts, more rarely megaloblasts, or transitional forms between these. 

 The amount of hemoglobin in the blood is diminished in leukemia but the 

 coloring of the individual corpuscles (abnormally decreased in numbers) need 

 not be diminished. An increase in the blood-plaques has also been observed 

 upon several occasions. 



The diagnosis of leukemia can be made without further consideration in 

 eases which show an extraordinary increase of the white blood-corpuscles, but 

 in doubtful cases the presence of the disease can only be determined by an 

 exact microscopical examination of the morphology of the leultocytes. 



Besides the increase in the white cells, what is particularly conspicuous in 

 the microscopic examination of leukemic blood is that in the majority of cases 

 the polynuclear cells are most numerous ; in other cases, however, the lympho- 

 cytes form the greater number, and this type of blood alteration persists dur- 

 ing the entire course of the illness. [In 41 cases of myelogenous leukemia 

 studied by me the polynuclear cells average 47.5 per cent. It is the polymor- 

 phous condition of the blood, the endless variety among the leukocyte forms, 

 that most impresses one in this disease.— Ed. ] We, therefore, quite properly 

 differentiate tivo different varieties of leukemia. 



