216 THE ACTION OF THE LIVING CELL 



In another series of experiments the technique was 

 modified to permit of a quantitative evaluation of 

 some of these findings. Cultures of B. coli were ob- 

 tained from the feces of the dogs used in this experi- 

 ment. Samples of blood were taken from the femoral 

 vein and from the branches of the mesenteric vein 

 near the junction of the jejunum and duodenum. The 

 jejunum was ligated at the duodenal junction and at 

 a point 10 cm. below this. Sterile broth was placed in 

 the jejunal loop so obtained and allowed to remain 

 sufficiently long to obtain a rich culture of the micro- 

 organisms present on the intestinal wall. This broth 

 culture was then removed by aspiration and replaced 

 by a 48-hour broth culture of the B. coli previously 

 obtained from the animals' feces and the abdomen 

 was closed. After ten hours the abdomen was re- 

 opened and portions of tissue were removed from 

 the duodenum near the pyloric junction and from por- 

 tions above and below the ligatures, for histological 

 examination. After washing, the mucosa of the duo- 

 denum, jejunum, and the upper part of the ileum were 

 scraped from the muscle walls. 



The blood samples, the mucosa and submucosa were 

 frozen in carbon dioxide to prevent decomposition, 

 and then dehydrated in vacuo over sulphuric acid. 

 The dry residues so obtained were weighed and then 

 brought into 2% suspension in 8% saline. These stock 

 suspensions were then diluted from twenty to two 

 hundred fold for subsequent experiments. One-cc. 

 portions of these various dilutions were mixed with 

 0.5 cc. of a forty-eight hour broth culture of B. coli 

 and incubated for 30 minutes. One-tenth cc. of these 

 mixtures was then injected into the marginal ear vein 



