ike an erupting volcano, the nineteenth century projected scientific exploration into the super strata of the macro- and microcosmos.  Miasmatic clouds lifted, as a retreating tide of vitalistic thought revealed stars on the beach of medical science: disciplines of medicine, dermatology, mycology, bacteriology, pathology, epidemiology, surgery, diagnostics, and more.  

     Physicians, botanists, dermatologists, and pathologists, spurred on by the advent of more powerful microscopes and ingenious culture techniques, linked various species of fungi to uniquely specific parasitic diseases of the skin.

     This paper concerns itself with the history, etiologic association, epidemiology, and treatment of a superficial fungal disease known in the 19^th century as Favus.   In the era concerned, the world was still mired in the ancient miasma (Latin "pollution") or "bad air" theory of disease. 

     Professor Moriz Kaposi (Ka'po shi ), a Hungarian physician working in the newly created Department of Dermatology at the University of Vienna, systematically collected data on various skin conditions.  He firmly rejected "miasmatists" and believed in the scientific, "germ" theory of disease.  Together with Prof. Ferdinand von Hebra, Chairman of the Department of Dermatology at the University of Vienna, Kaposi published information concerning "the vegetable (fungal) parasites of the skin," on which, in the main, this article is based.^[1]

Kaposi on Parasitic Dermatomycoses

A large proportion of cutaneous maladies are due to the influence of parasitic organisms.  In a natural classification,  these affections would be grouped together under the heading of  "parasitic dermatoses."

So far as the pathological changes in the tissues and disturbances of the nutrition of the skin are concerned, these maladies do not differ in any essential particulars from other  skin diseases, such as eczema, for hyperemia, exudation, inflammation, etc. are common  to all of them. 

But this group of diseases of the skin is distinguished by the fact, that a special influence which gives rise to them comes prominently into notice in a most peculiar manner, inasmuch as it is an essential constituent of the group of symptoms characterizing a disease, and, occasionally, may in fact, alone, form the chief feature by which the disease is recognized.^[1]

     The "chief feature" of each parasitic skin disease displayed itself to the examiner as the sine qua non of the malady in question.  In clinical and academic research at the University of Vienna, Kaposi immersed himself in the identifiable, "vegetable" parasites of skin, i.e. fungi, for, in his day, fungi were regarded as plants and bacteria as fungi (Schizomycetes or fission fungi).  Favus was a perplexing problem of childhood, which had been known for over 2000 years.  Dr. Kaposi approached this disorder with a keen, clear mind, which will be dissected in the following essay.  First, however, let us review the scope of his work and medicine of his day.

     In his day, Dr. Kaposi knew much about "animal parasites" of the human skin, including Sarcoptes scabiei-the "itch mite" of scabies, pediculosis (body lice), and other creature-infested skin disorders.  Kaposi's other major interests included the diagnosis and treatment of syphilis and lupus erythematosis.^[1]   In 1874, he identified and reported a deep purplish neoplasm found at times on elderly men of Mediterranean descent, now called  Kaposi's sarcoma.

     In order to accurately diagnose favus and other diseases, Kaposi and his colleagues used clinical examination as well as microscopic review of pertinent tissues and bodily discharges.  Culture apparati received samples of sputa, blood, urine, stool, skin, nail placed in broth, on egg, lemon peel, and apple slices.  Dr. Hallier, a botanist from Jena, created a complex culture apparatus composed of four stages, one of which included a sulfuric acid bath-filter, which, unfortunately, was breached by certain fungal elements, contaminating cultures.^[2]   Dr. Kaposi's concerns with favus will now be discussed.

     Celsus described an affliction of the scalp, most often in children, wherein the hair became lost or matted, with a buildup of honeycomb-shaped crusts dripping yellow liquid resembling honey.   He called this malady favus (fay' vus)(Latin "honeycomb"). Galen called it "meliceris"; Paul von Aëgina, "ceriones." ^[1] The Arabians (Rhazes) called the honey-like crusts "favus."  In the middle ages, physicians recorded cases of favus as tinea favosa (tinea = L. "gnawing worm," "ringworm"). 

     Ambrosius Paré, Mercurialis, and other physicians from the sixteenth and seventeenth centuries failed to give an exact account of favus.  Eighteenth century surgeons Turner, Rosen von Rosenstein and others did not define the disease in a meaningful fashion, whereas Lorry^[3] described a "tinea" which matched the special characteristics of favus.^[1]

     Plenk^[4] described favus of the scalp. Dr. Kaposi stated that herpes (tinea) tonsurans, i.e. tinea capitis, is  distinct from favus.^[1] Mahon reported that favus was contagious.^[5] Schönlein discovered the fungus of favus in the honeycomb crusts via microscopy^.[6]  A flurry of activity was engendered by this discovery, with a large number of pathologists, botanists and dermatologists swarming to study the parasite of favus.

     Remak ^[7] named the mould of favus Achorion Schönleinii, now Trichophyton Schönleinii, after its discoverer.   The achorion is a structure composed of densely-packed hyphæ, surrounding a hair shaft at the epidermis, creating the sulfur yellow scutulum of favus near the surface of the scalp epidermis, a specific feature of the disease, a sine qua non.  A few authors of the time continued to ascribe a secondary role to the Achorion, favoring miasmatic influence, despite ample scientific evidence to the contrary, favoring miasmata.^[8]  

Clinical Features

     Favus frequently appears in childhood.  Many of the young adult cases represent childhood cases growing up with the scalp parasite uncontrolled.  Favus is rarely seen in developed countries, but remains a problem in eastern Sub-Saharan Africa.  (See Photo 1. or view online) http://www.ifd.org/pictures/Tincap3.jpg            Photo 1.

     The parasitic fungus invades the outer epidermis adjacent to a hair shaft, encircles it in the outer horny layer of the scalp epidermis, producing a pustule.  The hyphæ multiply in a ring, forming a sulfur yellow plate which becomes the scutulum, pressing into the outer layers of the epidermis surrounding the hair. The fungus dives down outside the cuticle to the bulb, from there it invades the hair shaft, matriculating dorsally.

     This process repeats around other hairs, producing a honeycomb mosaic of scutulum forms, pressing in on the skin of the scalp, causing the patient to feel scalp "pressure" and "itching." (See Photo 2. or online)

 Online:   http://en.wikipedia.org/wiki/Favus                          

Complications include cicatrization alopecia of the scalp including totalis.  Favus may involve hairy smooth body parts, lanugo-haired smooth skin, beard, pubis, and nails. 

Etiology

     According to Sachs, there are two types of thallophyte: chlorophyllous thallophytes, e.g. algæ, and lichens, and those without chlorophyll, i.e. fungi.  Kaposi's scientific belief system maintained that morphologic study showed fungi to have arisen from algæ, hence, the interest of many botanists in the vegetable skin parasites.^[1]

     Later works of Hebra and skilled botanists such as Hallier pre-eminently discussed the general question of the relationship of favus to other mycoses and has thrown light on the subject, as well as placed the treatment of the disease on a rational basis.^9,10  Concerning the question of  Achorion schönleinii as the disease vector, rabbit inoculation with the favus fungus produced the typical findings of the disease, but some scientists took the demonstration to a new level:

Remak, in the year 1842, was the first to undertake the direct human inoculation of favus.  He fastened some favus crust on the dorsum of his left forearm by means of a sticking plaster.  After three or four days, the crust fell off without leaving any trace behind.  At the end of fourteen days, a red spot made its appearance, attended by itching and desquamation of the epidermis.  In its center, a pustule developed, and then dried up into a crust, and after this, there was a favus scutulum to be seen, which was demonstrated to consist of fungus elements^.[1]p.173.

Dr. Peyritsch made experiments with his own skin, under our observation, with the greatest accuracy.  He was most successful when he pricked the epidermis round a hair with a needle, and immediately placed a drop of water saturated with favus fungus on the spot, and allowed it to evaporate.^{[1] p. 163.}

Histopathology

     Hallier^[10] and Baumgarten grew Penicillium from favus samples, others Aspergillus or Mucor.  In addition to the special fungi stated, these observers saw other "species" develop in the culture as products of contamination. In the mid nineteenth century, the mycology held the "special fungi" mentioned above not  forms of fungal fructification.^[1]  Zürn produced an eruption, in rabbits, by inoculation of Penicillium, which was said to be indistinguishable from favus. "... neither the one nor the other is undoubtedly favus."^{[1] p. 172.}

      Favus fungus, viewed along the root sheath of a hair, shows gonidia (asexual spores) in chains running the long axis of a hair treated with KOH solution before microscopy.^{[1] p. 170.}  Examining  Achorion Schönleinii-One finds a predominance of gonidia varying greatly in size and shape, in a comparatively short and remarkably jointed mycelium (tubular cellular network), with a scarcity of smoothly-bordered mycelia. The mycelium breaks up readily into single cells.

Epidemiology

     Favus was extremely rare (mid 19^th century) in Austria, especially among the economically well-to-do.  A ten year study was carried out at the Vienna General Hospital, 1865-1874:  the findings:  25,935 cases of skin disease; favus cases: 48 males, 8 females = 56 persons per 10 years, or 0.215 favus cases per 1000 skin patients per year.^{[1] p. 175.} 

"By far the majority of cases of favus treated at Vienna at that time came from Austrian Poland and Russian Poland.  ...France appears to be extraordinarily rich in favus patients."^{[1] p.175.}

     From a communication made by Dr. Bergeron to the Paris Academy of Medicine, on Jan. 19, 1864, and quoted by Kleinhans,  It is to be inferred, "that no department of France is quite free from tinea favosa (favus)," and that tinea favosa is far more commonly met with, than tinea tonsurans.  In the south, round about Hérault, there are twenty cases of tinea favosa among every 1000 individuals.^{[1] p. 175.}  "Until lately favus was comparatively common in some parts of France, where it is a not infrequent cause of the rejection of conscripts for military service." ^[11]

Dr. Kaposi on the favus treatment:

We use olive oil, or cod oil, with or without balsam of Peru, with carbolic acid or without, and without any preference for one more than another.  What is essential is that fat in a fluid state, in such quantity that when rubbed in ... energetically, ... the favus masses become soft and rotten in a few hours.^{[1] p.183.}

The oil selected is rubbed in by means of an ordinary brush or a coarse painter's brush, and poured over the masses, so that it may quickly soak in; the scalp is then covered with a flannel hood.  After 2 or 3 hours the oiling is renewed. 

In the course of twelve to twenty-four hours, the thickest favus masses become softened.  They are removed with the fingers, holding  the hairs indiscriminately, and in thin tufts, between a blunt-edged instrument, such as  a tongue spatula blade and the opposed thumb, drawing them out painlessly, while preserving healthy hairs. Then the head is washed with soap, or spirit of potash-soap, and water, the favus fragments still remaining, being removed in that way, the scalp thoroughly cleansed.^{[1]p. 185.}

     In earlier times the so-called "pitch-cap" (la calotte)-a highly adhesive mass prepared by mixing pitch, vinegar, and flour,  spread on a cloth cap, was applied to the scalp and fixed firmly.  An assistant would seize the cap with both hands while the patient was firmly held, then tear it off a skillful and powerful jerk. 

     The hairs sticking out of the plaster would then be forcibly removed by the roots.  After various kinds of soaps, lotions, and salves had been rubbed in, a second or even a third application of the pitch-cap was made, at intervals of a few days or weeks, until total alopecia resulted.

     Gunn's treatment 1834: Shave the hair off as close as possible to the skin scalp-cleanse the sores daily with soapsuds and put on an ointment of 2 tablespoons tar, and a sufficient quantity of suet or lard to make an ointment plus one tablespoon of charcoal 2 teaspoonfuls of sulfur-spread on a bladder to wear as a cap. 

      Favus on the nonhairy (lanugo only) parts of the body: very quickly cured-a single or twofold unction of soft soap or cod oil softened the epidermal layers covering the honeycomb and the favus masses themselves, followed by a warm bath and thorough wash with soap suffices for the complete removal of the favus bodies.  Nails: extraction is the only quick cure-less painful to observe, for the tinea occasionally perishes spontaneously.^{[1] p. 187.}

Prof. Hallier

          Professor Hallier, Botanist, University Jena, contributed observations on the vegetable parasites of disease, parallel to Kaposi.  Hallier considered alien organic matter in tissues pathologically important -the "noteworthiness of organic pollution in the causation of disease."  He believed in a pleomorphic fungal form--the  Micrococcus--which could, under various ambient physical conditions of the host tissues (temperature, humidity, etc.), bring forth Penicillium, Aspergillus,or Mucor or other fungal forms in the occupied tissue.  

Hallier on Penicillium:

"Some of the sputa samples of a patient sick with measles, were placed on a divided lemon the 3d Feb; on the 7^th of Feb a vegetation of Penicillium was found, beside a 'Mucor-like fungus', which, however was entirely suppressed by the Penicillium." ^[2] (Is it possible the "mucor" was a bacterial colony suppressed by the Penicillium mold's secreted penicillin?)

Hallier on cholera:

Pacini et. al. very accurately attribute to one portion of the small cells (Micrococus) of Cholera discharges stools self infusorial-like motion , in contradistinction to molecular movement.^{[2] p. 78}

With a powerful system of a good microscope, one will ... perceive the motive organs of the small swarmers-oil immersion lens 1-18 of Merz.  The Micrococcus of "Mucor-kind"-the swarming cell-has a longer or shorter tail-like projection, as I have often exhibited in my designs-locomotive organs. ^{[2] pp. 77-78.}

      "With this system, by the help of ocular No. 4, I can perceive the tail, under the favorable western light of the morning or eastern light of the afternoon sun reflected from a still cloud to every ‘Micrococcus,' which, by its oscillation, produces its movement."^{[2]p. 78.}   (It is probable that  the swimming "Micrococcus" Hallier observed was in fact  Vibrio cholerae, the motile bacterium infecting the bowels  of cholera victims.) 

     The Italian MD Filippo Pacini discovered the cholera bacteria (Vibrio choleræ) in 1854, but his discovery was ignored by the Italian medical community, which held to the miasmatic theory of illness. Koch identified  V. cholera  as  the agent of the disease cholera, applying his four postulates of infectious disease causation. 

     In 1874, German debates on the microbiology of infectious disease concluded in 1874 that  "pleomorphic microbiology" and "organic pollution of tissues" useless in the pursuit of the  etiology of infectious diseases.  Hallier resigned his pursuit of botany  and vegetable parasites, delving into  the history and philosophy of medical science.^[13]

Conclusion

     The 19^th century blossomed with great advances in medical scientific thought, and in many other fields.  Invention drove the process, along with advances in education at all levels.  Thinkers broke away from old patterns of constraint, leading to organization, interpretation, and application of medical analysis, diagnosis, and treatment.  Miasma believers persisted during the century, but an avalanche of neo-medical theory and application blanketed conservatism.  Germ theory grew abreast monomorphic microbiology, and girded the advance of the scientific method.