ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



651 



presumptive tests for J>. eoli. 2. The bile-salt broth of RlacConkey and 



Hill also is a good medium for making rapid tests when the organism is 

 present in appreciable numbers. 3. The Smith solution is not so suc- 

 cessful as the foregoing for rapid diagnosis. 4. Endo's medium is of 

 inestimable value in determining the active presence of B. coli. 5. 

 Lactose litmus-agar does not react readilv to the small traces of acid 

 produced by different strains of the colon bacillus. 



Pipette-holder for Opsonic Work.* — E. C. L. Miller has devised a 

 special holder for opsonic or other small-calibred pipettes (fig. 152). 



Fig. 152. 



The long handle gives a firm grip on the pipette, while the screw enables 

 one to control the column of liquid very accurately. The glass pipette 

 can be introduced into the soft rubber stopper as readily and quickly as 



* Ceutralbl. Bakt., lte Abt. Orig., xlvi. (190S) pp. 730-1 (2 figs.). See also 

 Parke Davis and Co., Research Lab. Reports. 



