MINERAL COMPOSITION OF CROPS O 



the soil. Direct evidence of such relationships is, however, generally 

 difficult to obtain, because of the numerous factors involved and the 

 overlapping of these factors. Thus, climatic conditions may be such 

 as to cause in some years a significant reduction in the quantity of an 

 element in the plant or a marked change in the usual ratio of one 

 element to another. Mineral deficiencies in the animal may also be 

 due to an inadequate supply of food in general, to the unavailability 

 to the animal of the mineral elements in the plant, or to the species of 

 plant available to the grazing animal. Many of the factors causing 

 variations from the normal in plants are very closely interrelated, and 

 a discussion of them will be found in the second part of this review. 

 It is generally agreed, however, that frequently there are differences in 

 soils, often in the same locality, that are associated with the occurrence 

 of disorders in animals, and it is the purpose of this part of the review 

 to cite some of the observed characteristics of these soils. 



An appreciation of differences in the capabilities of soils to produce 

 healthful food for animals is not a recent achievement, for Neyen 

 (436) stated that Gleditsch in 1787 noted the occurrence of a bone 

 trouble of cattle in certain localities in Europe, and other early observa- 

 tions were made by Le Vaillant (555) and by Lichtenstein (350) in 

 their accounts of their travels in South Africa at the beginning of the 

 nineteenth century. Von Gohren (217) reported in 1861 that a disease 

 of the bones of cows occurred over a considerable region in Germany 

 in 1859, a year of drought. He associated the disease with a low con- 

 tent of inorganic elements in the feed, and he reported that the addi- 

 tion of bone meal to feeding stuffs cured the disease. Among other 

 early investigators of the relationship between the composition of the 

 forage and the occurrence of bone diseases were Grouven (230) in 

 1865, Karmrodt (310) in 1868, Roloff (498) in 1869, Klimmer and 

 Schmidt (317) in 1906, Scheunert, Schattke, and Lotsch (511) in 

 1911, and Zuntz (607) in 1912. All of these workers reported that the 

 calcium or phosphorus content of pasture or hay in the abnormal areas 

 differed from that in the healthful areas, and in many cases their 

 analyses indicate that these differences were real and significant. In 

 other cases, however, particularly where differences in calcium are 

 cited as being important, the minimum value of calcium given is often 

 not less than that now believed to be the minimum required by 

 animals (403, p. 354), which may indicate, of course, that certain of 

 the conclusions of these early investigators were not justified. It is 

 interesting to note, nevertheless, that considerable importance was 

 attached to soils and their properties as factors in animal health. 

 Later investigators may have been more accurate in some of their 

 classification of diseases, but many of them have not improved their 

 soil investigation technique to any important degree. 



A bone disease of livestock was first observed in Australia in 1895 

 by Potts (471) following a severe winter and a hot, dry summer. A 

 note of the investigator indicates that the soils involved were largely 

 formed from granites and that there was a scarcity of lime. Henry 

 (260, 261, 262) has reported that the occurrence of bone disease in 

 Australia was related to definite areas and soils that were often sharply 

 marked off from those parts of the same country where the disease 

 did not occur. 



Guthrie and coworkers (234) stated in 1914 that bone diseases in 

 Australia were generally most acute where the soils exhibited a marked 



