536 EXPERIMENTAL RESEARCHES WITH CHICKEN-CHOLERA MICROBES, 



The result of these experiments is somewhat marred by the 

 great mortality among the rabbits under observation, independent 

 of " chicken-cholera." Nevertheless it shows that, similar to 

 those obtained by Pasteur and his representatives, the possibility 

 of a transmission of the disease from rabbit to rabbit, under 

 conditions such as are described, is out of question. 



Ad 11. 



(a) On August 28th, 1888, eight full-grown rabbits (also two others for 

 immediate control) were fed on cabbage-leaves sprinkled with 2| ccm. 

 of active broth-culture * for each. They were thereupon placed with 

 sixtee7i uninfected rabbits (among which five half-grown) in special 

 enclosures containing an artificial burrow each. These artificial bur- 

 rows were constructed in the loose sandy soil which covers the surface 

 of the large wire-netting and wire-gauze enclosure, and fenced in, 

 at some distance, by rabbit-netting. They consisted in winding 

 and branching trenches, as nearly as possible five inches deep and 

 four and a half inches wide, covered with boards and soil so that 

 they could easily be uncovered and inspected. They were provided 

 with one entrance. + 



Three rabbits (one infected, two uninfected) were turned into each 

 of three small burrow-enclosures containing about 13' 6", 16', 16 '6" of 

 burrow, respectively ; into another, with about 58 running feet of 

 burrow, six rabbits (two infected, four uninfected) were let go ; the 

 last enclosure, in which were about 70 running feet of burrow, was 

 stocked with 7iine rabbits (three infected, six uninfected). Within 

 twenty-five minutes all twenty-four rabbits had found their way 

 inside the burrows in their respective enclosures. 



The eight infected rabbits (as well as the two others also fed on the 

 same quantity of contaminated food) promptly died from "chicken- 

 cholera," six outside, tivo inside the burrows. Their carcasses were 

 left untouched on the spot, where found, for three full days. 



Of the sixteen uninfected rabbits which, unless they died before, 

 were to be left in the enclosures for seven days from the beginning, six 

 in all (namely four full-grown, and two half -grown) died within this 

 time. But not in one instance could the cause from which they died 

 be identified as "chicken-cholera." 



* The history of this culture is as follows :— Colony from virulent blood of a rabbit fed on 

 culture, 10/ VIII. '88:^1. generation ; gelatine-stick-culture, 14/viii. — II. generation ; broth- 

 culture, 23/viii. = III. generation; broth-culture, 26/vni. = IV. generation. The latter 

 remained, before use, in a thermostat at 35-37° C. for two days. 



t They were constructed after data given by Mr. A. N. Pearson, of Melbourne, a member 

 of the Royal Commission. 



