206 THE HOUSE I LIVE IN. 



and leave it white. This white substance 

 is called ftbrine, and strongly resembles the 

 fibrous or thread-like substance of which I 

 have already told you the muscles are formed. 



The coloring matter, which we wash out, 

 consists of small round or globular particles, 

 which, before the blood coagulates, float in it ; 

 but, in the act of coagulation, become entan- 

 gled in the fibrine. You have also been in- 

 formed, in another place, that these globules 

 exist and float in the same way in the chyle, 

 before it mixes with the blood. In the chyle, 

 however, they are colorless. 



What gives the color to these globules in 

 the blood is unknown. Some suppose it is the 

 iron, or rather phosphate of iron. Phosphate 

 of iron, it is well known, exists in the blood, 

 in small quantity. Dr. Good thinks there is 

 about three ounces in an adult, and that there 

 is, of course, about enough in forty men to 

 make a ploughshare. 



I ought also to mention that sulphur is found 

 by chemists in the blood ; but they do not tell 

 us in what proportion. 



Thus we see that the three principal ingre- 

 dients of the blood are the coloring matter, the 



