22('» Journal op the Department of Agriculture. 



preference is for bones, and for this reason rotten bones represent one 

 of the most serious sources of danger. It must, however, be 

 emphasized that this most frequent source of toxin is not the most 

 toxic material available, and tliat a small amount of putrefying flesh 

 may frequently kill more rapidly than a large amount of rotten bones. 

 Any sort of carrion, of whatever origin, is liable to contain the toxin 

 and is therefore dangerous. Lamziekte has been produced experi- 

 mentally at Armoedsvlakte by drenching material obtained from the 

 carcass of a horse, an ox, a sheep, a lamb, a goat, a kid, a steeubok, 

 a mierkat, a fowl, and an ostrich. The toxicity of the material varies 

 with the nature of the material itself, with the stage of decomposition, 

 and with the conditions of putrefaction, but if the causal organism is 

 there no animal debris is safe. 



The most toxic material of alJ iias been prepared in the 

 laboratory, where the conditions of putrefaction are under control. 

 It is now quite easy to prepare laboratory carcass material (cultures 

 in minced liver) so toxic that O.UOOl gm. (less tlian a quarter- 

 millionth of an ounce) per kilogram l)ody-weiglit is fatal to cattle by 

 subcutaneous injection, i.e. less than half a grain can be made to 

 produce typical lamziekte in a beast weighing over 600 lb. 



When given by the mouth the amount of this laboratory carcass 

 material required is much larger, but even then less than a gram 

 (about one-tJiirtieth of an ounce) may prove fatal. In one experi- 

 ment 2i grams, or about one-tenth of an ounce, of what we regarded 

 as only moderately toxic material, produced typical lamziekte in a 

 beast weighing 700 lb. in less than a week. It is quite possible that 

 natural material in the veld may be found as toxic as our laboratory 

 product, but so far veld material has only been found which is capable 

 of producing the disease in quantities of one ounce or more. 



An animal showing marked craving may easily ingest several 

 ounces of obnoxious material or several pounds of less objectionable 

 stuff. Of bones, the natural selection of the craver, the quantity 

 ingested may be extraordinarily liigh. A marked craver will chew 

 bones for hours at a stretch. The behaviour of a batch of such cravers 

 l)efore a, testing trough of sterilized bones {vide infra) is characteristic 

 and noisy, the crunching and crackling being referred to by the staff 

 at Armoedsvlakte as the "bone concert." The actual quantity of 

 toxic bones required to produce lamziekte may vary from a few ounces 

 of stinking bones to a few pounds of slightly odorous bones. By the 

 time bones are bleached and "sweet" the toxicity has practically 

 disappeared, and owing to the selective tendencies of the cattle the 

 picking of such bones then tends to become a preventive of lamziekte 

 instead of a cause. This is what we call the " bone paradox " — bones 

 slay and bones save ! 



Other material, such as flesh, also becomes non-toxic in course of 

 time, but by reason of its chemical coini)Osition can never become 

 preventive of pica. 



The length of time material remains toxic on the veld is aot 

 known with certainty, but it must vary considerably with the time 

 of the year, the rate of putrefaction, and the weathering to which it 

 is subjected. Even bones can certainly remain toxic for over six 

 months, and other material probably longer. 



Within limits the rapidity of onset of lamziekte is prouurtioual 



