462 Observations on Inoculation with the Virus oj 



when the exudate from the diseased lung is introduced into the 

 system in the ordinary method of inoculation. 



Local and constitutional Effects of Inoculation. 



Inoculation with the virus of pleuro-pneumonia is performed 

 in various ways. The matter employed is either the serous exu- 

 date from the diseased lungs, the fluid from the deposit on the 

 surface of the membrane which lines the cavity of the chest, or 

 that from the sac in which the heart is enclosed. Generally the 

 fluid is obtained from the lungs when the disease is in the early 

 stage. Some operators contend that the only effective lymph is 

 found in the meshes of the fibrinous deposit on the lining mem- 

 brane of the chest ; others assert that the fluid which is found 

 in the membrane which invests the heart of a diseased animal is 

 the most effective and the safest material for inoculation. It may 

 be conceded at once that all these fluids will be equally active. 

 In their general and microscopic characters they cannot be dis- 

 tinguished, and the effects which follow their introduction into 

 the tissues of a healthy animal are the same in each case. 



The exudate which was employed in the experiments which 

 are to be referred to was taken from the lungs of animals which 

 had been slaughtered on account of pleuro-pneumonia : a portion 

 of the diseased lung was selected and suspended over a jar, into 

 which the exudate gradually flowed. 



When in its best condition the fluid is clear, yellow or light- 

 red in colour, the tint depending on the number of blood discs 

 which are present, viscid ; and if allowed to remain at rest it 

 coagulates, that is to say, a mass of fibrin is deposited ; the solu- 

 tion of which, however, can be effected by agitating the bottle 

 in which the material is contained. Under high powers of the 

 microscope the fluid presents the appearance which is depicted 

 in the folloAving illustration (Fig. 1). 



The chief features of the object are masses of germinal matter, 

 two of which are shown in the figure, the dotted lines indicating 

 the changes of form which occurred while the specimen was under 

 examination. Red blood discs are also seen at various parts of 

 the field ; some of these are circular in form, some oval, and 

 others have numerous small processes projecting from the sur- 

 face. In other parts of the field bacteria, bacteridia, and vibriones 

 are seen. 



Bacteridia, which are long dotted rods, having no independent 

 motion, are not always present in the exudate from a diseased 

 lung, but they are very commonly seen ; and it is worthy of 

 remark that they are constantly found in the blood of animals 

 which have died from certain forms of blood-poisoning. And 



