A second indication by Dr. Steiner concerned the use of horn manure. This had been manufactured at the Guldesmühle Mill, and it was further developed at Einsingen. In answer to a direct question as to the value of horn manure, Dr. Steiner replied that mixed with ordinary stable manure, horn manure was among the very best. Subsequently we asked Dr. Steiner whether roasted or unroasted horn-meal was better. (At Einsingen we do not roast it, whereas as a general rule the horn-shavings, etc., are first subjected to a very rigorous drying process. The advantage is that they are more easily ground down after this process. On the other hand, the roasting involved a loss of about 15 per cent, consisting mainly of water). Dr. Steiner answered to the effect that unroasted horn-meal was better on account of the higher hydrogen content. For the right influence of the manure, the hydrogen content was in fact far more important even than the nitrogen, though modern science had not yet awakened to the real importance of the hydrogen content for plant growth. (Steiner 2007:77)
STEINER, Rudolf. 2007. The Agriculture Course. (Trans.: George Adams) Shrewsbury: Wilding & Son Ltd.