THE PROGRESS OF SCIENCE 99 



Galea) whose gastric juice contains sulphuric acid. This free grastric 

 acid is distinctly antiseptic. 



We have now disposed in a certain fashion of our modes of defence 

 against foes from without ; but it is unfortunately as time in a physical 

 as it is in a moral sense that a man's foes are those of his own house- 

 hold. "We are liable to chemical assaults from within, whether from 

 poisons secreted by the bacteria inhabiting our internal organs or from 

 poisons arising from the imperfect digestion of our food. Food may 

 have poison in it at the time it is taken, the so-called ptomaines; but 

 poisons may be developed in it in consequence of its not undergoing 

 its digestion in a perfectly healthy fashion. All such digestive poisons 

 are dealt with by the liver. The liver is a very large gland placed in 

 such a position that all the blood coming from the organs of food- 

 absorption must pass through it on the way to the heart. 



The liver deals as best it can with the poison reaching it from the 

 intestine; in some cases, retaining it for a time, it eliminates it in an 

 altered form; in other cases it renders it innocuous and permits it to 

 reach the circulation whence it is removed by the kidneys. This power 

 of the liver is known as its (Ze-toxicating power. In this way is ex- 

 plained the well-known condition of being poisoned when the liver is 

 "out of order." When the liver is not doing its ^e-toxicating work 

 sufficiently well, not trapping poisons, these pass on into the blood- 

 stream and affect the whole body; the headache and the malaise being 

 the result in consciousness of this general chemical poisoning. Deranged 

 digestion, then, is responsible for the production of the poisons of auto- 

 intoxication which the liver should seize and render harmless. 



The chemical defences of some people are so feeble that they are 

 always on the verge of just not protecting them from the poisons of 

 their own intestines, so that such persons are hardly ever free from 

 headache. Other people suffer from periodical outbursts of poisoning 

 associated with one-sided headache (megrim or migraine). Some of 

 the sufferers from this distressing condition have been amongst the 

 most distinguished in science and literature, for Haller, Emil du 

 Bois Reymond, George Eliot and Sir James Simpson were all victims 

 of it. 



