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Scientific Proceedings (29). 



ammonium hydroxid gradually undergoes complete or nearly com- 

 plete transformation into the yellow needles. Under both condi- 

 tions the yellow needles form promptly, usually within an hour. 

 In the presence of too large an excess of iodine the reaction may 

 be prevented or hidden in the heavy black precipitate of iodonitro- 

 compounds. Too little iodine or too much protein also prevents 

 the reaction. 1 



We have confirmed practically all the statements made by 

 Bardach regarding the conditions affecting the production, as well 

 as the chemical and physical characters, of the yellow needles. 

 Bardach is convinced that, in spite of their iodoform-like odor and 

 color, the yellow needles do not consist of iodoform but of a 

 hitherto undescribed iodo-compound, which he proposes to pre- 

 pare in abundance for detailed investigation. In harmony with 

 Bardach's statements we have found the crystals practically insol- 

 uble in cold dilute mineral acids and alkalies, but somewhat solu- 

 ble in cold water. In alcohol, ether and chloroform the crystals 

 apparently undergo gradual modification into iodoform and prob- 

 ably other products. 



We have made no special effort to advance in this study in any 

 direction beyond the limits reached by Bardach himself, except to 

 ascertain whether other proteins than those named by Bardach 

 respond to the test. Applying the test as detailed above, we have 

 obtained strikingly positive results with the following additional 

 proteins and protein-containing materials : 



* myosin * ligament mucoid 



*edestin tendon mucoid (non-precipitable by 



* alkali albuminate (from myosin) acid) 



*acidalbumin (from muscle stroma bone mucoid (non-precipitable by 

 substance) acid) 



* heteromucoses * nucleoprotein (from ligament) 

 deuteromucoses gelatins (from ligament and bones) 

 elastoses j- osseoalbumoid 



tendomucoid digestive products (pep- f chondroalbumoid 

 tic, soluble, mixed, including j- ossein 



peptone) -j- collagen-elastin (mixed ; from bones) 



'When considerable protein and iodine are present, a grayish green precipitate is 

 apt to form at once on adding ammonium hydroxid. If the proportions are favorable 

 and the mixture is stirred continuously for a few minutes, the grayish green precipitate 

 undergoes a gradual and very beautiful transformation into the glistening yellow needles. 



