58 STUDIES IN ADVANCED PHYSIOLOGY. 



the presence of very small amounts of blood in any solution 

 can be established beyond a donbt. 



Haemoglobin shows a strong affinity for carbon monox- 

 ide, the poisonous substance which forms a large part of 

 ordinary illuminating gas. This affinity is in fact so strong 

 that when the haemoglobin has once united with the car- 

 bon monoxide it is almost impossible to displace it. This 

 fact renders gas poisoning extremely dangerous, for even 

 when such a patient is brought into the fresh air, he is 

 unable to get oxygen, because the haemoglobin will not let 

 go of its carbon monoxide, and so he is liable to suffocate 

 even in an oxygen atmosphere. Haemoglobin so united 

 with carbon monoxide has a bright arterial appearance, 

 and persons who have died of gas suffocation maintain the 

 bright arterial color even long after death. Such a corpse 

 retains a redness of skin which makes it at first sight seem 

 almost impossible that the individual should be dead. As 

 accidents of gas poisoning are not at all infrequent in 

 cities, it is worth while to know how to establish such a 

 cause of death. 



In addition to the haemoglobin, which amounts in a 

 dried corpuscle to over, ninety per cent., there is an albu- 

 men called globulin, further traces of fat, and of two organic 

 substances, cholesterin and lecithin (to be studied further in 

 later chapters), and finally salts of potassium, phosphates, 

 and traces of ordinary common salt. In the live condition 

 of the corpuscle a large quantity of water enters into its 

 constitution. 



6. Consistency. In consistency the red corpuscle seems 

 to be made up of a homogeneous, jelly-like substance 

 which possesses remarkable powers of elasticity. In exam- 

 ining the blood streaming through the blood vessels one 

 may find here and there a corpuscle caught where an artery 

 divides, very much stretched out of its natural shape, yet 

 springing back to its original form as soon as the stress is 

 over. This is no doubt a valuable property in enabling the 



