In 1893 O'Brine, from Colorado, and Mayo, from Kansas, reported on their work with the loco plants. O'Brine failed to isolate any alkaloidal or other poisonous body, and his feeding experiments on himself and on rabbits having failed, he sums up in despair: "The more I examine the loco question, the more I am persuaded that we must look for some other cause besides the loco-weed."[132] At the end of his report he gives some ash analyses but fails to interpret them. He also fails to give details as to the method of obtaining and estimating his ash. O'Brine's ash analyses are as follows: KEY TO ASH ANALYSIS: A = SiO_{2}. B = Fe_{2}O_{3} and Al_{2}O_{3}. C = CaO. D = MgO. E = K_{2}O. F = Na_{2}O. G = H_{2}SO_{4} H = Cl. I = P_{2}O_{5}. J = CO_{2} ------+-----+-----+-----+-----+----+-----+----+----+----+----+-----+ Plant.|Total| | | | | | | | | | | |ash. | A | B | C | D | E | F | G | H | I | J | ------+-----+-----+-----+-----+----+-----+----+----+----+----+-----+ AM |12.15|32.77|16.26| 6.05|3.11|13.30|3.21|3.9 |0.47|6.12|10.55| | | | | | | | | | | | | AL |13.52|17.08|12.21|14.27|2.62|17.26|5.75|3.22|3.87|3.30|17.37| | | | | | | | | | | | | AC |12.36| 7.82| 5.97|12.10|3.55|23.35|3.38|5.56|9.0 |4.67|20.62| | | | | | | | | | | | | ------+-----+-----+-----+-----+----+-----+----+----+----+----+-----+ KEY TO PLANTS: AM = _Astragalus mollissimus_ (whole plant) AL = _Aragallus lamberti_ (whole plant) AS = _Astragalus caryocarpus_ These analyses are evidently incorrect, as O'Brine estimates a carbon content of 4.13 per cent for the first, and for the second 2.22 per cent, showing incomplete combustion. Mayo[133] experimented with alcoholic and aqueous extracts of dried _Astragalus mollissimus_ on guinea pigs, with negative results, and was first led to deny a relationship between the disease and the plants. Later, as a result of the post-mortem findings, he was convinced that his first conclusion was wrong and that "the disease is certainly the result of animals feeding upon the loco-weed." Mayo says: A careful survey of the experiments performed and observations noted leads me to the opinion that the disease known as "loco" is the result of malnutrition, or a gradual starvation, caused by the animals eating the plants known as "loco weeds," either _Astragalus mollissimus_ or _Aragallus lamberti_. If there is a narcotic principle in the plant, chemists have failed to find it and a fluid extract does not possess it, and a ton of the plant eaten by an animal ought to contain enough of the poisonous properties to destroy an animal.