last.  The first emigrants found the Hottentots in possession of prodigious herds of fine cattle, but no horses, asses, or camels.  The original cattle, which may still be seen in some parts of the frontier, must have been brought south from the north-northeast, for from this point the natives universally ascribe their original migration.  They brought cattle, sheep, goats, and dogs; why not the horse, the delight of savage hordes?  Horses thrive well in the Cape Colony when imported.  Naturalists point out certain mountain ranges as limiting the habitat of certain classes of animals; but there is no Cordillera in Africa to answer that purpose, there being no visible barrier between the northeastern Arabs and the Hottentot tribes to prevent the different hordes, as they felt their way southward, from indulging their taste for the possession of this noble animal.

I am here led to notice an invisible barrier, more insurmountable than mountain ranges, but which is not opposed to the southern progress of cattle, goats, and sheep.  The tsetse would prove a barrier only until its well-defined habitat was known, but the disease passing under the term of horse-sickness (peripneumonia) exists in such virulence over nearly seven degrees of latitude that no precaution would be sufficient to save these animals.  The horse is so liable to this disease, that only by great care in stabling can he be kept any where between 20 Deg. and 27 Deg.  S. during the time between December and April.  The winter, beginning in the latter month, is the only period in which Englishmen can hunt on horseback, and they are in danger of losing all their studs some months before December.  To this disease the horse is especially exposed, and it is almost always fatal.  One attack, however, seems to secure immunity from a second.  Cattle, too, are subject to it, but only at intervals of a few, sometimes many years; but it never makes a clean sweep of the whole cattle of a village, as it would do of a troop of fifty horses.  This barrier, then, seems to explain the absence of the horse among the Hottentots, though it is not opposed to the southern migration of cattle, sheep, and goats.

When the flesh of animals that have died of this disease is eaten, it causes a malignant carbuncle, which, when it appears over any important organ, proves rapidly fatal.  It is more especially dangerous over the pit of the stomach.  The effects of the poison have been experienced by missionaries who had eaten properly cooked food, the flesh of sheep really but not visibly affected by the disease.  The virus in the flesh of the animal is destroyed neither by boiling nor roasting.  This fact, of which we have had innumerable examples, shows the superiority of experiments on a large scale to those of acute and able physiologists and chemists in the laboratory, for a well known physician of Paris, after careful investigation, considered that the virus in such cases was completely neutralized by boiling.