Bread From Stones by Julius Hensel

Translated from the German writings of Julius Hensel, the book Bread From Stones was designed to introduce the people of the U.S. to the idea that plants require healthy food in order to flourish, just as a human being does. It describes a then-new and rational system for fertilization which has become science today — fertilizing with stone dust.

In the excerpt below, Hensel dives into the chemicals which are found in various fields with different mineral makeups, and the plant species which flourish within.


Front cover image of Bread From Stones book

Copyright 1991, softcover, 102 pages.

From Chapter 2: Healthy and Unhealthy Produce

According to the chemical examination of the ashes which remain when plants are incinerated, the average result shows about as much potash and soda as lime and magnesia. Silicic acid is somewhat more than one-fifth of the sum of these four bases, chlorine about one-twentieth of the whole, phosphoric acid is one-sixth, but sulfuric acid is only one-fourth in weight of the phosphoric acid.

Granite rocks contain an average of 6% of potassa and soda, while their contents of phosphoric acid are more than 1%, granite by itself will readily fulfill the demands for vegetable growth, as may be confirmed by a report in the papers received while writing this. We read:

“In Deutmansdorf, Kreis Loewenberg, in Silesia, were found on the heap of refuse from the quarries three stalks of rye with ears containing 90 to 100 grains.” (General Anzeiger fur Schlesien and Posen, October 1, 1893.)

As to chlorine, this mostly reaches our cultivated plants through manuring with liquid manure containing salt, and has been proved directly injurious to the growth and quality of many plants. In this respect it is sufficient to point to the evil effects of manuring tobacco with liquid manure. Chlorine is not found in wheat, rye, barley and oats, millet and buckwheat, linseed, apples and pears, plums and gooseberries, acorns and chestnuts, nor in the wood of any forest trees. We need, therefore, not consider chlorine in fertilizing our fields.

Now, when I state that the given proportions of the ashes have yielded this average in comparing more than 80 analyses of the ash of the various parts of plants, it need not be concluded from this that any particular plant, or the particular part of a plant, needs a quite definite proportion of ashy constituents, but it is found on the contrary that the earthy constituents of the same kind of plants differ in various ways.

This explains why we find the same species of plants to flourish now in calcareous soil, now on soil formed from granite, gneiss or porphyry as an example of which I shall only mention sheep’s-yarrow, Achillea millefolium. This is effected in great part by the fact that potassa and soda are interchangeable, but these two alkalis may also be replaced in most plants to a considerable part by the alkaline earths, line and magnesia; but, of course, the nutritive value of the plants and the other qualities cannot then remain the same.

Potassa and soda may even be wholly lacking in a plant and they may be entirely replaced by line and magnesia. As this fact is not as yet found in any book, I cannot refuse a challenge as to proof. I name as my witnesses the royal mason, Wimmel, of Berlin, and engineer Klug, of Landshut. In company with the gentlemen I visited, on June 25th, of this year (1893), the loftily situated marble quarry near Rothenzechau.

In the neighborhood of this marble quarry the vegetation is always somewhat behind in time to that of the valley, by the end of May, they have passed away. We found such dandelions there growing immediately in the marble rock, where this had water flowing over it, and the flower stalks reached the height of about a foot and a half. There was not, indeed, any great wealth of leaves, and the thick and high flowerstalks themselves could be broken like glass into pieces, which I did not weary in repeating before the eyes of my companions.

Now this Silesian marble is a very white dolomite, consisting, therefore, of carbonate of lime and carbonate of magnesia; but it must also surely contain besides this some phosphate and sulfate of lime besides a trace of carbonate of protoxide of iron, the presence of which is demonstrated in the moist clefts of the marble by a brown oxidation. These plants, therefore, grew on a sub-stratum of almost pure lime and magnesia.

This extreme example convinces us that the alkaline earths (lime and magnesia) may really replace the alkalis (potassa and soda) in the building up of plants, and this also furnishes us with the explanation why the iron-slag, as a preeminently calcareous fertilizer, unmistakably caused an increase of crops on fields which were deficient in lime. The same result might, indeed, have been reached more cheaply by directly spreading the lime on them. But there is another “But” in this matter, for in harvests it is not merely the quantity, but much more the quality which has to be considered.

Even if the striking example cited makes it manifest that lime may in great part replace the alkalis in building up plants, giving to them the same form, and, indeed, making them of imposing size, nevertheless the quality and the internal worth of the products of the soil is considerably influenced by the difference in its basic constituents. I, therefore, mentioned, not unintentionally, that the flower stalks of the dandelions grown on marble could be broken like glass into separate pieces, while on the contrary dandelions stalks growing on soil containing potassa may be bent into rings and formed into chains, as is frequently done by children. Potassa makes pliable and soft, lime makes hard and brittle. Flax is a very good example of this.

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About Julius Hensel

Dr. Julius Hensel was born July 11, 1833, in Küstrin, Germany, and died approximately around 1903 in Berlin. Hensel was a German agricultural and physiological chemist or pharmacist, who later qualified as a doctor of medicine. Described as one of the greatest pioneers of biochemistry, he was considered by his followers as the “inventor” of the mineral field fertilization with “rock flour”. He published “Macrobiotic” in 1882, where he suggested that the underlying cause of all disease is a lack of mineral substances which are essential to the functioning of the body’s cells. As he traveled, he studied the minerals of the country and recorded any health problems more common in the area. His work was often controversial, but he continued to study and learn, releasing Bread from Stones in 1893.