M. Dumas on the Constitution of Milk and Blood. 137 



Nothing is easier than to compare the serum and globules 

 of a normal blood with the serum and globules of the same 

 blood modified by the intervention of a substance capable of 

 changing the direction or the intensity of the powers of en- 

 dosmose between the globules and the serum. 



In the blood of a living animal the globules suspended in 

 the liquid may absorb or lose some of their elements, if we 

 succeed in changing the constitution of the serum ; but how 

 long will the phenomenon last? If the substance added be 

 mischievous it will be eliminated ; the veins on their part will 

 absorb liquids destined to reestablish the equilibrium, and the 

 experiment will soon be so altered that the little differences 

 that we have to measure will disappear, vanishing before great 

 complications. 



On the contrary, if we withdraw the blood from the body of 

 the animal and divide it into two parts of equal weight, one 

 destined to furnish the term of comparison, and the other to 

 receive the substances modificative of the power of endosmose, 

 coagulation and what I have called the asphyxia and death 

 of the globules will soon do away with any hope of arriving at 

 certain results. 



It was therefore necessary to receive the blood into a vessel, 

 to oppose its coagulation, and to replace towards it the action 

 both of the heart and lungs — that is to say, to keep the blood 

 in movement and to present it in a very divided state to the 

 action of oxygen or of the air. I arranged an apparatus 

 which fulfilled these conditions, and allowed one to ascertain 

 how alcohol, neutral salts of soda or potash, sugar, &c. act 

 when added to the serum, and how the interior liquids con- 

 tained in the globules may become modified under their influ- 

 ence either in quantity or in nature. 



While I followed out these views, preoccupied by the evident 

 invasion of scurvy in the general state of health of the inhabi- 

 tants of Paris towards the close of the siege, and whilst I sought 

 to make up by applicable means for the absence of all fresh vege- 

 tables and of all fruit in their habitual diet, a foreign doctor, 

 Dr. J. Sinclair, by following out the ideas which he had 

 heard me teach upon this subject, was led to seek in them the 

 explanation of the first symptoms of alcoholism, a state which 

 he designates by the name of dypsomania. 



Just as scurvy would have as its primary cause an im- 

 poverishment of the serum in potash-salts and a surcharge of 

 salts of soda (which favours the exosmose of the potash of the 

 globules and consequently their destruction), so alcoholism 

 would have as its starting-point the presence of alcohol in the 

 serum of the blood and its effects on the globules. 



