1896 DISEASES OF THE CIRCULATORY SYSTEM 



which lies the stroma, in the form of a network of protoplasmic 

 threads and nodes, which contains the haemoglobin, and in the 

 saucer-shaped corpuscle forms a cap over the archoplasm, which lies 

 just over the concavity of the saucer. 



2. The archoplasm is composed of a central clear hsemoglobin-free 

 area, and is composed of a glassy body, which is rest material, and 

 which in ordinary cells forms the achromatic spindle in mitosis. 

 Excentrically placed and surrounded by the glassy body hes the 

 capsule corpuscle, near which lie two sharply defined bodies embedded 

 in a substance which may contain a vacuole. These are the 

 centrioles, 



3. The blood plate is the metamorphosed nucleus of the normo- 

 blast, which lies excentrically on one side of the archoplasm. It is 

 easily extruded in making the blood film, and gives rise to the blood 

 platelets which are so well knowm. Its peculiar appearance is 

 possibly due to physiological modification during mitosis of the 

 normoblast. 



4. Meve's plastokonten are granular bodies of unknown nature 

 scattered through the erythrocyte, but mostly seen near the 

 archoplasm. 



As we shall see later, these various parts of the erythrocyte are the 

 explanation of the intracorpuscular blood puzzles and the origin of 

 the numerous intracorpuscular pseudo-parasites of many observers. 



The red corpuscles number some five millions in a healthy male, 

 and some four and a half millions in a healthy adult female under 

 the climacteric age, but there are physiological increases of these 

 numbers in infancy, by cold and at high altitudes, while race has 

 but little influence. 



Pathologically they can be increased by mechanical means — 

 e.g., the concentration of the blood caused by diarrhoea, sweating, 

 vomiting, and polyuria, or by heart disease. They can also be in- 

 creased in toxic conditions and in polycythemic splenomegaty. 

 They may be decreased by any mechanical, toxic, or parasitic cause 

 which induces blood destruction. 



The normoblasts of the bone-marrow may accidentally occur in 

 the normal circulating blood as an isolated form, but in numbers 

 they indicate that there is an abnormal demand for erythrocytes- — 

 as, for example, after a haemorrhage. A normoblast is about the 

 same size as an erythrocyte (7-5 microns), but contains a rounded 

 nucleus composed of a nuclear membrane containing dense chro- 

 matin and measuring about 4 microns. 



The megaloblasts may be found in the circulating blood if some 

 toxin is attacking the bone-marrow. They are usually of large size 

 (20 microns), but this is not their characteristic, which is the large 

 nucleus measuring some 10 microns and containing loosely arranged 

 chromatin. The nucleus may undergo the usual changes, and the 

 megaloblast become a megalocyte. 



Microblasts are small cells or abnormal normoblasts or megalo- 

 blasts. 



