OF INSECTIVOROUS PLANTS 453 



Unopened Pitchers 



The prolonged midrib or tendril, which carries the pitcher, was severed 

 at the end of the basal part of the lamina; and that portion of the tendril, 

 which interfered with the subsequent manipulation, was removed. 

 Sterile scissors were always used in cutting the plant tissues. The top 

 portion of the pitcher was rapidly passed through the flame, and was 

 then cut off. The cut edge of the pitcher was then rapidly flammed; 

 and the Uquor was immediately withdrawn by means of a sterile pipette, 

 and plated in the usual way on plain nutrient agar. The liquor from 

 12 unopened pitchers was studied in this manner, and was invariably 

 found to be sterile, as was shown by the absence of colonies on the plates 

 after incubation for 4 days. 



Opened Pitchers 



The liquor was removed from opened pitchers with sterile pipettes, 

 placed in sterile test tubes, and immediately plated. 



Partly opened pitchers, free from insects, were used in two experi- 

 ments. The liquor from each of these pitchers contained a goodly num- 

 ber of bacteria which grew on plain nutrient agar. 



The remaining experiments were conducted on liquor from open, 

 active pitchers, containing insect remains. The number of bacteria 

 present in 1 cc. of liquor was determined in each of five pitchers with 

 the following result: — 



Pitcher 1 450,000 



2 8,000,000 



3 1,200,000 



4 1,900,000 



5 48,000 



The morphology of these bacteria was studied. Smears were made 

 from several colonies, which differed in physical appearance, and were 

 stained with Loeffler's alkaline methylene blue. All the micro-organisms 

 were rod-like, and therefore belonged to the family of the Bacteriaceae. 

 A few of the organisms contained spores; none of them produced gas 

 when inoculated into lactose bile-salt bouillon. 



The Hquor in an old pitcher, which was becoming brown at the top, 

 contained 104,000 bacteria per cc. 



Gelatin. In two experiments, gelatin plates were poured. The bac- 

 teria grew and completely liquefied the gelatin in 48 hours. 



