Serum Therapy

Anti-toxin Sera.

Of the anti-toxin sera, diphtheria anti-toxin is rightly regarded as the most efficient. Its use, now almost uni versal, has been largely responsible for the reduction of the death rate from diphtheria (see INFECTIOUS FEVERS) in a most striking manner from over 33% in pre-anti-toxin days to about 7 per cent. This latter figure includes all cases in all stages, but if treatment is instituted on the first day of disease the mortality falls to zero. Tetanus anti-toxin is also of great value, but owing chiefly to the fact that Tetanus (q.v.) is rarely diagnosed until the toxin has se cured a firm hold upon nervous elements, it has not achieved a position as a therapeutic agent equal to that occupied by diph theria anti-toxin. On the other hand the mass of evidence accum ulated in the World War clearly demonstrates the necessity for its use in the prophylactic treatment of earth-soiled wounds. Gas gangrene, rife during the early days of the World War, led to the production of highly efficient anti-sera for the toxins of B. welchii and the vibrion septique, the necessity for which has largely passed. Another serum, for the neutralisation of the toxin of bacillus botulinus—a germ which gives rise to a particularly fatal type of food poisoning fortunately rare in the British Isles— is also prepared but there is little evidence available as to its efficiency (see FOOD POISONING).

Finally, Calmette has obtained an anti-toxic serum, "anti venene," from horses which he had immunised against both colu brine and viperine venoms.

Anti-bacterial Sera.

Many varieties of anti-bacterial sera have been prepared against many of the microbes of the second group, but few of them have stood the test of time; and at the present day only anti-streptococcic, anti-meningococcic, anti pneumococcic, anti-anthrax and anti-dysentery sera remain. These

have established their positions in the therapeutic armament largely as the result of recent acquisitions to our knowledge of the biology of certain microbes but in part also to improvements in the methods of preparing anti-sera.

The recognition that numberless strains of streptococci exist which though morphologically identical are biologically diverse has resulted in the preparation of polyvalent sera which some times produce dramatic recoveries in apparently hopeless cases of septicaemia, although in other instances serum is employed with out avail. In the case of infections by the pneumococcus too, sev eral different types may be encountered to some of which no cura tive serum could be prepared. Within recent years these organisms have been classed into four different groups of which the two first were alone amenable to serum treatment—that designated Type I being particularly so. Similarly, and largely as the result of re searches necessitated by the prevalence of the so-called "spotted fever" (see SPINAL MENINGITIS) during the War the meningo cocci have been grouped under four types and whilst multivalent sera comprising anti-bodies for all types have been made, the use of appropriate univalent sera has afforded even more successful results. The two anti-sera prepared against pathogenic bacilli, anti-anthrax and anti-dysentery, are both of very considerable value. The first has long been employed either alone or in con junction with operative measures in the treatment of "malignant pustule," but the position of the latter depends almost entirely upon the ample demonstration of its value in the War provided it is used early in the disease. (J. W. E.)