86 



III— Histopathologic Study. 



4 hours of immunisation. 



Rabit 368-Weieht 1.050 gn. 



Inoculated on Jan. 26 th 1921 at 12.55 p. m. in mar- 

 g4Mal vein, of ear with 1 cc. of saline solution with 1 

 foopful (2 milligrs.) of a 24 hours' gélose culture of B. 

 paratyphi A. in suspension and sterilised by heating in 

 a water-bath at 65oC. forean hour. 



Leucocytes (blood taken at 1.05 p. m.)=-8 800 per 

 imm^ (average). 



Leucocytes AjJood taken at 1.42 p. m.)=15 800 per 

 snins (average). 



Killed (violent narcosis with chloroform) at 4.44 p. m. 



Autopsy. — Bone-marrow red, with 

 'Whitish areas; shining surface. Consis- 

 tence fù*ra, slightly reduced. Central vein 

 anoderately turgid. 



Histologic Study— The arrangement 

 of the parenchyma cells in groups occu- 

 pying the spaces between the fat-cells 

 is altered; the cells are disarranged and 

 less numerous than under normal condi- 

 tions. The most plentiful cells are the 

 polymorphonuclear leucocytes; these so- 

 metimes arrange themselves round a fat 

 cell like a crown (Fig. 14, Plate 17). 

 Polymorphonuclear leucocytes are also 

 lo be seen occupying the territory of a 

 fat-cell (Fig. 1.5, Plate 17), which would 

 indicate a marked chemotaxis of the fat- 

 cell for poljTiiorphonuclear leucocytes. 



The blood spaces are slightly dilated; 

 there is also an inconspicuous oedema 

 of the reticulum. 



The fat-cells keep their normal vo- 

 lume, 



Itabbit 309-WeiKbt 1 MO {rs. 



Inoculated on Jan. 28 th 1921 at 1.000 p. m. in mar- 

 3,ilial vein of (2 millisramms) of a 21 hours' culture on 

 slanting gélose of B. paratyphi A. sterilised by heating 

 in a water-bath at 65oC. for an hour. 



Number of leucocytes (counted at 1.13 p. in.)=-5 000 

 per mm' (average). 



Killed by violent narcosis (chloroform) at 4.57 p. ra. 

 (3.57 hours after the commencent of immunisation). 



Autopsy. — The bone-marrow has 

 approximately the same appearance as 

 in rabbit 368; its consistence is per- 

 liaps slightly firmei'. 



Microscopic Study. — The appearaiT-» 

 ce is approximately the same as the 

 one described in rabbit 368- slight con- 

 gestion, inconspicuous oedema of reti- 

 culum, fat-cells with normal volume, di- 

 sorder in the arrangement of the paren- 

 chj'ma-cells and abundance of polymor- 

 phonuclear leucocytes, grouping of these 

 cells round the fat-cells; the latter have 

 a well-preserved nucleus and some of 

 them are entirely covered bj' polymor- 

 phonuclear leucocytes which appear to- 

 their surface (chimiotaxis) (Fig. 15, Pla- 

 te 17). 



The elements of the haemoglobin- 

 containing class of cells are in this 

 case more abundant than in rabbit 368. 



At the end of the first four hours of 

 immunisation, the bone-marrow of rab- 

 bits 368 and 369 show a slight conges- 

 tion, inconspicuous oedema of reticu- 

 lum and a disorder in the arrangement 

 ot the parenchyma cells, which are less 

 numerous than under normal conditions, 

 and above all an intense transformation 

 of myelocytes into polymorphonuclear 

 leucocytes. The latter cells arrange them- 

 selues like a halo round some of the fat- 

 cells; at other times a greater number of 

 them make up a focus round a fat-cell. 

 The aspects indicated would suggest a 

 marked chemitaxis of the fat cells for 

 polymorphonuclear leucocytes in this ini- 

 tial stage. 



17 hours of immunisation. 



Rabbit 210-Weight I 300 gn. 



Inoculated on April 7 th 1920 in margina! vein of ear 

 with 1 cc. of a sterilised emulsion of B. paratyphi A. 

 (Emulsion A). 



Died during the night before 9 a. m. on April 8 tk 

 1920. 



Autopsy -Tht bone-marrow (femur) has a light red 

 colour, a shining surface and a normal consitance. 



Histologic Study.— Under a weak po- 

 wer the section shows on a backgroimd 

 stained by eosin a more or less imiform 

 rose colour small circular light areas» 

 which correspond to fat-cells; the pa- 

 renchyma cells are considerably redu- 



