DERMATITIS 13 



this group, also the forms that produce aspergillosis, one type of which oc- 

 curs in the ear. 



The Mucoraceae produce an unsegmented mycelium and septa only where 

 the reproductive bodies are formed; the spores usually occur in sporangia, or 

 occasionally small spores may be found in the mycelium ; zygospores which result 

 from fertilization also occur in some species. Several species produce surface 

 lesions. 



According to Neumann, the dermatophytes of domestic animals belong to 

 six distinct genera of fungi as follows : Trichophyton, Eidamella, Microsporon, 

 Achorion, Lophophyton, and Oospora. These genera are not, however, all 

 accepted by botanists. 



Trichophyton was established by Malmsten in 1848 and is characterized by 

 having a mycelium consisting of simple or dichotomously branched filaments 

 and producing spores from 4-9 ^ long. Sabouraud, however, divides the genus 

 into several species depending on the position of the fungus with regard to 

 the invaded hair. The T. endothrix lives inside the hair; the T. ectothrix 

 develops outside of the hair, forming a sheath around it, and the T. endo-ecto- 

 thrlx develops both inside and outside the hair. This classification is scarcely 

 tenable from either clinical or cultural characters. We have placed this genus 

 with Sporotrichum. 



The Eidamella spinosa described by Matruchot and Dassonville in 1901, has 

 a much branched mycelium, 1.5 /u, in diameter, divided into short segments and 

 splitting into somewhat squarish oval bodies; it is found on the dog. 



The Microsporon discovered by Gruby in 1843, has a branched mycelium, 

 the latter branches bearing conidia from 2-3 p in diameter. This fungus has 

 also been placed with Sporotrichum. 



The Lophophyton, described by Matruchot and Dassonville in 1899, pro- 

 duces a mycelium with some tortuous filaments, others short curved, with thick 

 curved walls; no spores produced; it occurs on fowls and is also referred to 

 Sporotrichum. 



The Achorion was described by Remak in 1833. The filaments of the 

 mycelium are from 2-3 jj, in diameter, flexuose or straight, variously branched; 

 finally breaking up into spores. This fungus has been placed with the genus 

 Oospora. 



Oospora was described by Wallroth in 1833. Its mycelial threads are 

 2-3 fji in diameter, arranged in irregular chains. 



The best expert account of dermatomycosis so far as it affects lower animals 

 will be found in the treatise by Neumann * who includes also an excellent 

 bibliography on the subject. Hutyra and Marek have a German text which 

 devotes considerable space to the subject. The work by Hyde and Montgomery 

 treats the subject from a human standpoint. The work by Plaut is also an 

 exhaustive treatise. 



Etiology. The cause has been ascribed to various fungi which will be 

 described later in the present work. The predisposing causes are unclean- 

 liness, weakness of animals (those that are worn out may offer a 

 favorable medium for the attacks of the fungus). In the case of cows, 

 Fleming observes that the disease is common in the winter when the stables 

 are dirty, and disappears in the spring when the animals are turned out to 



l "A Treatise on the Parasites and Parasitic Diseases of the Domesticated Animals." 

 English Translation by George Fleming. Second Edition Revised and Edited by James 

 MacQueen. 697. 365 f. 1907. New York. 



