10 PLANT DISEASE 



haemoglobin in the blood, we must also admit 

 that there must be a corresponding variation 

 in the quantity of oxygen taken into the 

 system, and carbonic debris discharged, these 

 being the special functions of the haemo- 

 globin. 



It is obvious, therefore, that an animal having 

 a normal or rich haemoglobin will absorb much 

 more oxygen into the system and discharge 

 much more carbonic debris than will an anaemic 

 animal. 



And the extent to which the non-performance 

 of these vital functions may extend, is measured 

 by the fact above noticed, that it is possible 

 for the proportion of haemoglobin in the blood 

 to fall to one- twelfth of the normal. 



Another important point in connexion with 

 a defective haemoglobin is that 



" In breathing, nearly equal volumes of 

 carbonic acid are lost and oxygen gained. 

 Small quantities of other gases are given off 

 from the lungs, including organic matter, 

 which is exceedingly capable of putrefying, and 

 which is no doubt highly injurious and the 

 cause of much ill-health and of many diseases 



