74 HISTOLOG I ' OF XI T TRIENT FLl-IDS. 



The loss of blood necessary to produce death varies accord- 

 ing to age, nutrition, etc. The loss of one pound generally 

 produces syncope, and of four to six pounds usually causes 

 death. In newborn children the loss of a few ounces is dan- 

 gerous. In pernicious anaemia the only pathological change 

 is progressive and extreme diminution in the number of red 

 corpuscles. In some cases the number of red globules is re- 

 duced to 500,000 per cubic millimeter. Several forms of ap- 

 paratus for counting the corpuscles have been devised. That 

 of Zeiss, after Thoma, is simply an eye-piece micrometer 

 divided into squares, with a device for mixing the blood with 

 a 3 per cent solution of chloride of sodium, in the proportion 

 of 99 parts to I of blood. The area of the squares being 

 known, it is easy to calculate the number. 



4. Leucaemia or leucocythamia is an increase in the number 

 of white corpuscles, with a decrease of red ones, so that from 

 the normal standard of I to about 300 red globules they may 

 be i in 20, or even less. There is usually hyperplasia, or 

 increased size, of the lymph apparatus, either spleen, lymph 

 glands, or bone marrow, singly or combined. Mild cases 

 may be transitory, as in pregnancy and many diseases. The 

 white cells in leucaemic blood are of different sizes, and on 

 this account some have tried to locate their origin, but unsat- 

 isfactorily. Occasionally in this disease needle-like octohedral 

 crystals, called Charot's crystals, are found in the blood. 

 Erlich has recently shown a difference in white blood cells in 

 their power of absorbing eosin. He terms such as absorb it, 

 eosinophilous cells, and considers them multiplied in disease 

 of the blood-making organs, while ordinary white cells are 

 alone increased in acute cases of leucocytosis. 



5. Poikilocytosis. Under this name is described the irregular 

 forms of blood discs occurring in debilitating diseases, espe- 

 cially in progressive pernicious anaemia. A large number of 

 minute cells have given rise to the term micro cythcemia, and 

 abnormally large cells to macrocythaemia. Such terms are 

 unnecessary. In the account given of the structure of red 

 corpuscles the presence of cells of various sizes and irregular 

 forms was referred to in normal blood. As some blood cells 



