BUREAU OF ANIMAL INDUSTRY. 685 



DESCRIPTION OF PLATES. 



FhATE I.— Ulcerated cfpcum of a pig inoculated with blood from a case of hog- 

 cholera. The entire mucous membrane has undergone necrosis. Near 

 the valve, in the upper portion of the figure, the early stage, that of 

 ecchymosis, is still to be seen. The valve is slit open to show the intact 

 mucosa of the ileum. This figure also serves to illustrate the appear- 

 ance presented bv the caecum and colon when pigs have been fed with 

 pure cultures, the only difference being that in the latter case the necro- 

 sis is at first superficial. In the figure it involves the entire thickness 

 of the mucosa, having begun in the submucosa, whither the bacteria 

 have been carried by the blood. 

 Plate II.— Ulcerated ccecum of a pig fed with viscera from a case of hog-cholera. 

 The c£ecum is slit open to show the mucous membrane quite imiformly 

 necrosed, with isolated deeper ulcerations. The ileo-c^cal valve is very 

 much thickened, the mucous membrane ecchymosed and ulcerated. 

 The lymphatic glands of the meso-colon and in the angle formed by the 

 entrance of the ileum into the c^cum a«-e purplish, with cortex en- 

 gorged with extra vasated blood. They illustrate the condition of the 

 lymphatics of both thorax and abdomen in the acute hemorrhagic form 

 of the disease. 

 Plate III, Fig. 1. — Cover-glass preparations from the spleen of a rabbit inoculated 

 with the bacterium of hog-cholera from Nebraska. Stained for a few 

 minutes in an aqueous solution of methyl violet, mounted in xylol-bal- 

 sal. I)ra^^^l with camera lucida, Zeiss Vs homogeneous, ocular 3. x 1110 

 The bacteria are seen among dilTiisely stained cells. They are chiefly 

 in pairs, in some of which the process of division is not yet completed. 



YiQ. 2. — Cover-glass preparation from the liver of a rabbit inoculated with the 

 microbe of pneumonia in pigs. Stained in an alkaline solution of methy- 

 lene blue. Mounted and drawn as stated in Fig. 1. The colored portion 

 33 confined to the two poles, the central region remaining colorless. 

 Plate IV, Fig. 1. — Culture twenty-eight days old in a tube of nutrient gelatine of 

 the microbe causing pneumonia in pigs. The cvilture was prej^ared from 

 the internal organs of a rabbit which had been inoculated from a cult- 

 ure obtained originally from Geneseo, 111. 



Fig. 2. — Culture eleven days old of the same microbe obtained from Sodorus, lU. 

 Both natural size. 



Fig. 3. — Colonies of the same microbe on a gelatine plate seven days old. x 60. 

 The pale peripheral zone, which appears after three or four days in beef 

 infusion peptone contairung 10 per cent, gelatine, together with darker 

 granular nucleus, is very constant. 



Fig. 4. — Gelatine tube culture from the blood of a rabbit inoculated with a cult- 

 ure of the hog-cholera bacterium from Sodorus, lU. , ten days old. 



Fig. 5. — T'abc culture of the hog-cholera bacterium inoculated from cultures of 

 the spleen obtained from Sodorus, 111. , fourteen days old. 



In Figs. 4 and 5 the two modes of surface growth of the hog-cholera 

 bacterium are illustrated, both distinguishable from Figs. 1 and 2. See 

 Plate V. 



Fig. 6. — Colonies of hog-cholera bacteria on a gelatine plate four days old 

 xlOO. 

 Plate V, Fig. 1. — Surface growth in gelatine tubes, enlarged tv/o diameters. 



a. Bacterium of hog-cholera, growing as an irregular patch, flattened, 

 witii a jagged margin and occasional slender branches, and as a convex 

 rounded head. 



b. Microbe of pneumonia, growing as a very thin pearly patch, with 

 lobcd margin, often showing faint concentric lines when viewed ob- 

 liquely, a, twenty days old; 5, twenty-six days old. 



Fig. 2. — Gelatine tube culture of a bacterium v/hich resembles the bacterium of 

 hog-cholera very clo.sely, but which difl'ers in its physiological proper- 

 ties, and which "has no pathogenic effect on animals. Found associated 

 with the microbe of pneumonia in the spleen of a pig (Geneseo, 111.). 

 Culture about a week old. The surface growth is very vigorous, cover- 

 ing after a time the gelatine completely. The peculiar mesh- work shown 

 m the figure is a constant character. 



Fig. 3. — Growth of the bacterium of hog-cholera on potato twelve days after 

 inoculation. 



