COLLOIDS 93 



ing it in a mortar to facilitate the action of strong acids 

 or by melting it at a temperature of about 1000, one would 

 destroy not only the instrument which tells time but also 

 those landmarks which might permit us to identify the 

 individual role of each of them in the function of the whole; 

 that is, in the movement of the hands." 



But since then we have learned to do better/ By sub- 

 mitting an albumin to an action less brutal than that, for 

 example, of gastro-intestinal digestion, we may break it 

 down little by little without destroying the entire complexes 



"the wheels" which compose it, and by continuing in 

 this way through a series of successive disintegrations, we 

 would find that every albumin which is a colloid is at last 

 split to amino-acids which are crystalloids. We know that 

 the molecules of a salt in solution coalesce one with another to 

 form crystals when there is not enough solvent to keep them 

 a certain distance apart, but we do not know how and why 

 amines, which can exist as free molecules, and which then 

 obey the laws of salt solutions may congregate into such 

 complex elements as colloids. 



It would be especially interesting to know by what physi- 

 cal or chemical agent (electricity, magnetism, affinity) these 

 molecules of amino-acids are bound and held together. We 

 will know this certainly some time. At the moment we 

 must confine our study to the biologic and physicochemical 

 properties of the albumin as we find it in its complex medium 

 and to the substances which result from its successive dis- 

 integrations. Although incomplete, this study already gives 

 us a series of interesting reflections which are sufficiently 

 exact for our purpose ; to learn how and why an organism can 

 become diseased, and perhaps also how it can recover under 

 the best conditions. 



We have then determined that of all the products of the 

 disintegration of an albumin, those only are antigens which 

 are still in the colloidal state. 



Free amino-acids are no longer antigens. There is here a 

 confirmation of the fact which we have noted above, that 

 only colloids can be antigens and it is possible to conclude 

 from this that foreign albumins taken as a food which gastro- 



