Occurrence. Etiology. 303 



annual losses of sheep from pox amounted to more than one-eighth 

 of the total number of animals, further Heintl, in 1823, gives the 

 annual loss in Austria as 400,000 animals, and in France it is claimed 

 that in 1819 more than one million sheep fell victims to the disease. 



Germany was entirely free in the years 1889-1899, the disease however appeared 

 in 1900 in a township of the Governmental District Liineberg (220 cases with 

 two deaths). In the following year it was discovered in four townships of the 

 government districts Konigsberg and Gunibinnen, aifecting 100.5 sheep, of which 

 38 succumbed. The country was free from the disease for one and a half years, 

 but it reappeared in the above districts, as well as in Marienwerder in 190.3, 

 and on this occasion 1157 sheep became affected, of which 465 died. It is supposed 

 that at this time the disease had been brought in by smugglers or butchers from 

 Eussia. Two years later it was brought from Russia into Eastern Prussia, by 

 agricultural laborers, where 20 townships with 30 farms, and isolated farms in 

 Saxony and Anhalt, were infected. The total cases amounted to 3,220 sheep, 704 

 of which succumbed. Since that time several outbreaks have been observed annually 

 in Prussia, and in the year 1908 4 townships with 402 cases, and 154 deaths, were 

 recorded. 



The disease formerly raged in a severe form in France, especially in the 

 Southern provinces, but also occurred in other parts of the country, especially after 

 the importation of sheep from foreign countries was restricted while large numbers 

 were imported from Algeria. 



Austria was free from the disease in 1894, but since that time this has again 

 become widely spread, especially in the years 1898-1900 in Tyrol, and still more 

 in Dalmatia; in the latter year 21,575 sheep in 72 townships were affected, and 

 of these 10,007 died or were slaughtered. After that time the disease diminished 

 greatly, and no outbreaks have occurred since 1903. 



The disease was always more or less confined in Hungary to the Southeastern 

 part, and in recent times it occurs almost exclusively in the counties which are 

 adjacent to Roumania and Servia. From 1899 to 1908 an average of 59 townships 

 were infected, with 15,275 cases, of which 2,175 died. Since 1904 the dit^ease 

 attained again a greater extension, and occurred in 1908 in 113 townships of 

 27 counties with 19,131 cases, the total deaths being 4,443. 



In the same year 466 townships were affected in Bulgaria; 40,744 in Eoumania; 

 in European Eussia 23,034 animals became affected. The disease also frequently 

 occurs in Spain, while the other European countries have been free for many 

 years. It is widely sprea<l in Asia, and is also known in Africa (Egypt, Algeria), 

 while there are no statistics relative to its occurrence in America and Australia. 



Etiology. Eegarding the nature of the virus, it is at present 

 only known that in diluted pox lymph and under great pressure 

 it passes the porous Chamberland filters (F* and F**). The 

 filtrate is not even under highest power found to contain formed 

 bodies, and attempts at cultivation fail to give positive results 

 (Borrel). 



Tenacity. In glass tubes, closed on both ends by melting, and kept in dark 

 and moderately cool places, the pox lymph retains its virulence even for two years. 

 At a somewhat higher temperature, for instance at 35° it is active for months. 

 Its virulence is attenuated by higher temperatures, and at 48° it is destroyed 

 in a short time, while when subjected to a cold of — 12-15° it does not become 

 attenuated for two months (Nocard). Glycerin attenuates it proportionately to 

 its quantity, and a mixture of equal parts of lymph and glycerin becomes avirulent 

 in 12 days when kept at a temperature of 25° (Duclert). Of the disinfectants a 

 3% boracic acid, or 2% sodium salicylate have hardly any influence on the lymph 

 (Galtier) and likewise 2% sulphate of zinc and 10% chlorate of lime solutions are 

 ineffective (Peuch). Putrefaction, diluted hydrochloric acid, li/±% carbolic acid, 

 21/^%, sulphuric acid, 10% wine vinegar, spirits of turpentine (Griinwald) and 

 also a mild iodine solution (1:10000) (Peuch) exert a quick destructive action 

 on the lymph. The virus dies in the fleece of sheep affected with pox, at the 

 latest in two months (Duclert & Conte). 



Experience gained in practice also points to the considerable resistance of 

 the pox virus. When kept in a moderately warm place, protected from draughts, 



