[nicholls] blood sera IN TUBERCULOUS INFECTION 13 



ly, although the pigs were unaffected. This was probably due to inter- 

 ference with the feeding, for the injections produced extensive areas of 

 coagulation-necrosis in the abdominal wall and in one or two instances 

 there was slight superficial suppuration. Apparently the injections of 

 serum had some slight deterrent effect on the development of the 

 tuberculous lesions, but it was felt that it was unwise to draw any 

 positive conclusions from such a small series of animals, particularly 

 with so mild a germ, so a second experiment was undertaken on 

 similar lines but with several modifications suggested by the experience 

 with the former series. 



Experiment II. 



Six guinea-pigs and twelve rabbits were placed under exactly the 

 same conditions as to food, exercise, etc., and weighed at intervals of a 

 week until an average normal weight was established. They were then 

 grouped in pairs as nearly as possible according to the weight Eectal 

 temperatures were taken daily for ten days to establish a mean normal 

 temperature. Both the weights and the temperatures were found to 

 vary in health between rather wide limits. The average temperature of 

 ihe pigs was from 102° and 3-lOths to 102° and 8-lOths; that of the 

 rabbits from 102° to 103° and 2-lOths. 



All with the exception of two rabbits, which were retained as con- 

 trols, were inoculated with one c. cm. of an emulsion of a more virulent, 

 though still mild, culture of the tubercle bacillus in normal saline, 

 standardized as before. One-half of the animals were given the inocula- 

 tion in the left leg subcutaneously; the other half, mtraperitoneally. 

 Three days after inoculation one member of each pair was given a sub- 

 cutaneous injection of one c. cm. of a fresh supply of normal seruni 

 from the same goat, collected with the same precautions as before. This 

 was repeated every third day till the close of the experiment. The rea- 

 son for reducing the dose was that the injection of the larger amounts 

 (if serum in the first series of animals produced much local disturbance. 

 Two rabbits were given serum alone without bacilli, so as to act as con- 

 trols. During the course of the investigation daily temperatures were 

 taken and the animals were weighed weekly. A few of the animals died 

 spontaneously before the six weeks allotted to the experiment had 

 elapsed, but the remainder were killed in pairs on the same day A 

 post-mortem was made immediately under strict aseptic conditions. In 

 I'stiniating the amount of disease resulting, I took into consideration 

 the dissemination of the disease in the various organs, the amount of 

 tissue destruction, the amount of repair, if any, the histological appear- 

 ance of the lesions, and the morphology of the bacilli found. This 

 necessitated the preparation of about two hundred microscopic pre- 



