81 



Rabbit 373-WeigJit 14IW grs. 



Feb. 4 t)i 1921— Leucocytes (1.25 p. iii.; ^16 550 per 

 mm3 (average). 



Inoculated at 1.10 p. lu. on s.inie day with 1 cc of 

 saline solution with a loopful (itrated for 2 niilligramms) 

 of a killed 24 hours gélose culture of B. paratyphi A. 

 The injection was carried out uneventfully. 



Feb. n th 1921— At 2.00 p. m. the rabbit died. It 

 was at once atitopsied. 



Aí/fopsí/.— Subject in strongly ema- 

 ciated. Viscera-lungs, liver, spleen, heart 

 and kidneys show a normal aspect. The- 

 re is no pneumonia, coccidiosis lesions 

 or myxoma. 



Bone-marrow of a more or less firm 

 consistence; it is pale in ill-defined trac- 

 ts, brownish-red in others and is ra- 

 ther opaque than otherwise. 



Histologic study.— The lesions of the 

 bone-marrow are of the same kind as 

 tliose of rabbit 218, with slight indivi- 

 dual differences. The parenchyma cells 

 ai'e less abimdant than in rabbit 218; 

 there is active hyperplasia of the mye- 

 loid cells, which group themselves roimd 

 the vessels and make up foci in the 

 substance of the parenchyma. 



The polymorphonuclear leucocytes, 

 in opposition to the previous case, are 

 very numerous, as niunerous as the mye- 

 locytes. 



The fat cells are noticeably smaller 

 than normal fat-cells. Erythrogenetic 

 groups are not conspicuous. 



The lesions of the bone-marrow on 

 the 7th dag of immunisation are chiefly 

 hyperplasia or intense proliferation of 

 myelocijtes, which group themselves ro- 

 und the vessels in a quite evident way; 

 the evolution of myelocytes towards po- 

 lymorphonuclear leucocytes goes on in 

 an active way; there is individual varia- 

 tion with regard to the numerical preva- 

 lence of these two kinds of cells. 



There is persistance of the capillary 

 congestion; the oedema of the reticulum 

 ¿s inconspicuous. 



The fat-cells are reduced in volume; 

 some of them, however, have already re- 



gained their size; others are hidden b^ 

 the hyperplastic myelocytes. 



Cells belonging to the class of the 

 haemoglobin-containing cells are found, 

 but are very much less conspicuous than 

 those belonging to the myeloid class of 

 the myelocytes. 



Small foci of fibrosis (proliferation 

 of connective tissue cells) are plentiful, 

 and indicate, probably, the organitation 

 of small hœmorrhagic foci. 



i 0th Day of Immunisation. 



Rabbit 405-(l)- Weight 050 grs. 



April 11 th 1921— Leucocytes^ 14 400 per raras ^ave- 

 rage). 



April 11 th 1921 -J^T. 20 p. m.) Leucocytes=16 500 

 per mm3 ^average). 



April 14 th 1921— (41.10 p. m.) Leucocytes=-18 450 

 per ram3 (average). 



April 15 th 1921— (12.40 p. m.) Leucocytes=19 550 

 per mms (average^. 



April 16 th 1921- (12.35 p. ni.^ Le«cocytes=15 333 

 per mm* ^average). 



On April 16 th 1921 he was inoculated intraperito- 

 neally with 1 loopful (2 milligramms) of a 24 hours cul- 

 ture on slanting gélose of B, paratyphi A. killed by 

 heahring in a water-bath during an hour at 65oC. 



April 26 th 1921— Killed by violent narcosis with 

 chloroform at 2.15 p. m. 



Death occured after 1.15 niins. 



Autopsy— Tht bone-marrow did not show any ma- 

 croscopic lesions. 



Rabbit 408-Welght 1.140 gn. 



April 28 th 1921— (1-40 p. m.)— Leucocytes^lO 950 

 per mms ("12 300=11 600=10 600=8 600). 



May 4 th 1921— (1.30 p. ra.)— Leucocytes= 15 950 per 

 inmJ ^16 800=14 800=14 600=13 600). 



May 5 th 1921— (2.05 p. ra.)— Leucocytes=19 400 per 

 mm3. 



May 6 th 1921— (1.00 p. m )— Leucocytes =12 850 per 

 mm3 (13 000=12 400=11 600=10 400). 



On May 6 th 1921, at 1.45 p. m, , this rabbit was 

 inoculated subcutaneously with a loopful (2 milligramms) 

 of a 24 hours culture on gelosa of a B. paratyphi A. In 

 suspension in saline solution and sterilised by heating in 

 a water-bath at 65oC. (1 hour). 



May 16 th 1921— The rabbit was killed by violent 

 narcrosis with chloroform (15 mins.). 



(1) This rabbit (405), which showed an abnormal 

 number of leucocytes in the days preceding immunisation» 

 was used nevertheles.s for our studies, as the lesions of 

 the bone-marrow were perfectly similar to those found 

 In the following rabbits which had a normal number oi 

 leucocytes. 



