This fact, confirmed in the mind of the bacteriologist by the fallacious system of diseasing animals as ‘témoins’ or ‘controls,’ has given rise to the dangerous theory that all contagious diseases may be forestalled in their most deadly form by the inoculation of human beings with diluted virus produced by those diseases. This dangerous belief has been widely fostered by the unfortunate educational influence of the law of compulsory vaccination. But it must be observed that vaccination, unlike inoculation, does not introduce any products of the special disease--small-pox--into the system. The vaccine disease in the cow is not small-pox, nor can it ever be made to produce small-pox. The preservative power which is claimed for it, therefore, has not the dangers which are attached to inoculation, but neither can it claim the occasional immunity which may attend that dangerous practice of introducing small-pox virus into the blood. Pure air, cleanliness, and decent house-room secured to all our people, form the true prophylaxis of small-pox. _Exaggeration of Bacteriology._--We observe how neglect of the Law of Unity is misleading the intellect in relation to bacteriology. This subject, useful if pursued without cruelty and in subordination to higher facts, has become a mischievous exaggeration[7] both as to what it signifies and as to what it may lead to. The majority of our active and intelligent medical investigators are now intensely engaged in the search for a microbe as the primary _cause_ of every disease known to humanity. Cancer, leprosy, fevers, hydrophobia, diphtheria, tetanus, insanity, etc., are being largely studied by this imperfect method, in hope of finding a characteristic microbe which can be pronounced the essential cause of the disease. The great mental energy of biological investigators is diverted from sanitary investigation to the search for fresh bacilli. Admirable perseverance, acute ingenuity, unwearied energy are devoted to this search. Advantage has been taken of the helplessness of the lower animals to carry on a system of experimentation upon them, the extent and ruthlessness of which has never before been attempted. Disease is studiously propagated. Myriads of healthy living creatures are filled with loathsome disease in order to furnish ‘material’ for experimentation. So many kilos of dog or rabbit (used for injecting disease, or noted as more or less slowly resisting the death thus gradually inflicted) is a common expression now used in experimentation, and supposed to give ‘scientific accuracy’ to experiments. It is a pitiful intellectual fallacy of short-sighted materialism that supposes it possible to obtain ‘scientific accuracy’ by regarding so many kilos of living dog as if they could be experimented on as so many kilos of dead matter, or as if they were the materials of a steam-engine, which can be taken apart, examined, cleaned, tested, and put together again in complete working order.