16 MANUAL OF POISONOUS PLANTS 



small depressions, grey at their base. These result from the opening of the 

 pustules, of which some may be found at the margin of the patch. The hairs 

 are not broken, but shed, and the condition is, in fact a suppurating folliculitis." 



The symptoms observed in the bovine, as described by Neumann, are as 

 follows : "The commencement is manifested by a slightly salient ring, on the 

 surface of which the hairs are erect. An active proliferation of the epidermis 

 causes the rapid formation of scales more or less adherent to each other, and 

 crusts of 2 mm. to 7 mm. thick — hence; the name dartre crouteuse was given 

 to the affection by the older (French) veterinarians. According to Gerlach, the 

 crusts are thicker on dark skins, on which they have a greyish-white, fibrous 

 appearance, resembling the amianthus (porrigo asbestinea) on white skins, which 

 are usually finer, the crust is thinner and a little yellow in color." 



Diagnosis. The diagnosis based on clinical symptoms should be veri- 

 fied by microscopical examinations. It is best to take material from 

 the younger and deeper parts of the crust which may be moistened with 

 water, or a better examination can be made if it is boiled with a 40 per cent 

 solution of potash after which the particles can be dissected and the fungus 

 threads and spores made out. The different forms cannot readily be distin- 

 guished except by cultural methods. The organism grows readily on nutrient 

 media that are neutral or with slightly alkaline reaction. Sabouraud recom- 

 mended the following: 



Pure glycerine, glucose, lactose, or maltose 4 grammes 



Granulated petone 1 gramme 



Distilled water 100 grammes 



Gelose 1 . 50 grammes 



Solid media like potato, agar, and peptonized bouillon are favorable media 

 while liquid media are less favorable. Growth may occur at 1S°C, the optimum 

 being 30° C. 



Prognosis. The duration of the disease depends on circumstances, it grad- 

 ually diminishes and may disappear without medical aid. The average length of 

 time of the disease is 40-50 days. Cleanliness has much to do with its disap- 

 pearance. It lasts longer in thick coated animals than in those with thin coats. 



Treatment. Cleanliness and sanitary surroundings, disinfection of stables, 

 careful and regular grooming (all articles used in this process having 

 been thoroughly disinfected, especially when they have previously been 

 used on a diseased animal), avoiding any substance that causes irri- 

 tation. The following preparations have begn used with success : Mercury 

 1-500; carbolized glycerine; alcohol; an ointment composed of 1 part of carbolic 

 acid, hard and soft soaps, each 20 parts. Fourie and La Calve recommend pure 

 carbolic acid, tincture of iodine, and chloral hydrate in equal parts. The ap- 

 plications should be made once or twice a day or every other day depending 

 upon the irritant properties of the preparations used. 



For bovines, the remedies named above will prove efficacious; for the dog, 

 application of an ointment prepared from 1-5 per cent of nitrate of silver, is 

 satisfactory. 



