Examination of Bardach's new Protein Test. 127 



* tendomucoid digestive residues (pep- f elastins (from ligament and tendon) 



ligament mucoid digestive products egg yolk (aqueous emulsion) 

 (peptic, soluble, mixed, including synovia 



* chondromucoids 



*In dilute ammoniacal solution. 



f Dilute solution, chiefly of hydration products, obtained by heating in dilute 

 ammonium or potassium hydroxid. 



It was found, on allowing the crystalline mixtures to stand 

 for several days, that each precipitate diminished in amount very 

 perceptibly and, also, on longer standing, that the crystals lost 

 their characteristic canary -yellow color ; they became opaque and 

 when viewed through a microscope their outlines were less distinct 

 than immediately after their formation. 



The needle-like crystals obtained with the above named pro- 

 tein materials differed somewhat in character. The needles de- 

 rived from some proteins were much finer and sharper than others. 

 In some cases the needles were hair-like in appearance. As a rule 

 the crystals were the same in each test with a given protein. 

 Many of the crystals arranged themselves in rosettes or in bundle- 

 like clusters ; a few had a knobbed structure which gave them 

 the appearance of nails. Some of the needles were branched like 

 twigs of evergreen. It was a question whether the type of crystal 

 was characteristic of the particular protein, or whether the differ- 

 ences in crystal-form were due to variations in the rapidity or other 

 physical conditions of formation. It is probable, of course, that 

 variations in the proportions of the reagents employed may have 

 introduced chemical factors affecting the nature of the crystalline 

 products. Iodoform crystals were mixed with the needle-like 

 crystals whenever the proportion of protein was relatively low. 



Whether Bardach's reaction is exhibited also by any non-pro- 

 tein substances has not been determined. It is probable, from the 

 results of our own work, that without exception every soluble pro- 

 tein will give it. The test is quite delicate and promises to be 

 useful in many ways, but its comparative value, and the disturbing 

 influences in its application, 1 as a protein test await determination. 



tic) 



proteose-peptone (Witte's) 



peptone) 

 osseomucoids 



serum (dog blood) 



lime water extract of tendon 



1 Bardach has already noted a disturbing influence of earthy phosphate. Bardach : 

 loc. cit., p. 357. 



