OCCURRENCE AND FORMA TION OF GROWTH SUBSTANCES 63 



Kostermans (1934, Mitt. XIII) have identified heteroauxin in 

 yeast, Rhizopus nigricans, and Aspergillus niger. 



Van der Weij (1933a, h) demonstrated growth substance in an 

 alga Valonia macrophysa. None was found in the setae of 

 Pellia epiphylla (Overbeck, 1934). 



Plant Products. — In the hght of the wide distribution of growth 

 substance in higher and lower plants, it is reasonable to expect its 

 presence in some of the plant products of commerce. Seubert 

 (1925) found growth-promoting properties in malt. Kogl, 

 Haagen Smit, and Erxleben (1933, Mitt. VII) reported a signifi- 

 cant amount of it in salad oil (perhaps peanut oil) ; however, the 

 growth substance was not present in a free form. It could be 

 demonstrated after saponification by treatment with hydro- 

 chloric acid or pancreas Hpase. Not all salad oils that were 

 tested gave positive results; in certain other oils, for example, 

 maize oil, free growth substance was found. Maschmann and 

 Laibach (1933) demonstrated growth substance in flour made 

 from oats and rye and found it in various kinds of bread. Accord- 

 ing to Kogl, Erxleben and Haagen Smit, (1934, Mitt. IX), both 

 auxin a and auxin b occur in peanut, sunflower, mustard, and 

 linseed oils. 



Boysen Jensen (1931b) obtained a significant test for the growth 

 hormone in a preparation of Witte peptone. The hormone may 

 have been formed by the action of bacteria or fungi during the 

 manufacture of the product. 



Human and Animal Organisms. — Seubert (1925) made the 

 remarkable discovery that significant amounts of growth sub- 

 stance are present in human saliva; this was the first time that the 

 compound was found outside plants. Kogl and Haagen Smit 

 (1931, Mitt. I) (see also Kogl, 1932, and 1932, Mitt. II) 

 showed later that human and animal urine contains a great deal 

 of growth substance. 



The presence of growth substance in animal organs has been 

 demonstrated by Maschmann (1932), Maschmann and Laibach 

 (1932, 1933), and Kogl, Haagen Smit, and Tonnis (1933, Mitt. 

 VIII) and in maUgnant growths by Maschmann (1932). 

 Whether or not it plays a part in tumor growth is doubtful 

 (Kogl, Haagen Smit, and Tonnis, 1933, Mitt. VIII), even though 

 carcinoma showed a higher concentration of growth substance 

 than neighboring normal tissue. Navez and Kropp (1934) 



