﻿ILLUSTRATIONS 



(Photomicrographs by Charles Martin) 



Plate I 



Fig. 1. Spores of Aspergillus. Two isolated and two in one droplet. 

 Freshly isolated and unstained. The amount of condensed 

 moisture proper for isolation is shown in this figure. 



2. Spore of Bacillus subtilis isolated in a drop of liquid. Freshly 

 isolated and unstained. 



3 to 7, inclusive. Bacterium coli commune. This series was obtained 

 as follows : One organism was isolated in broth plus a little serum. 

 When it was divided into two, a daughter cell was picked up and 

 transferred to a new droplet. When this had divided, a cell was 

 transferred to a third droplet. After four successive transfers, 

 a series of 5 droplets was obtained containing respectively 1, 2, 

 4, 8, and 16 bacilli — the offspring of the individuals left behind at 

 each transfer. The cover glass was dried and the bacilli stained 

 on the cover without the loss of a single one from the series. 

 The diameter of the droplets was, on the average, about equal 

 to the length of the chain of 8. 



Plate II 



Fig. 1. Larva of Culex injected with mercury by means of the inoculation 

 pipette. 

 2. Antenna of the larva of Culex shown in fig. 1. This was dissected 

 away, and after removal injected with mercury with the in- 

 oculation pipette. The point of the pipette was introduced 

 between the spherical and the elongated masses of mercury. 



TEXT FIGURES 



(Text figures 9 and 19 by courtesy of The Journal of Infectious Diseases. Drawings of other 

 text figures by Moscaira and Espinosa) 



Fig. 1. Pipette holder containing a pipette (pip), cl, clamp by which 

 the holder is fastened to the metal plate pb; ud, up-and-down 

 adjustment governed by screw s; rl, right-and-left adjustment 

 governed by screw s'; g, groove in which the pipette is held by 

 plate tp; ic, isolating chamber; H, hood of pasteboard for pro- 

 tecting the end of the isolation chamber. 



2. Top of pipette holder, rl, right-and left adjustment governed by 



screw s'; g, groove in which the pipette is held by plate tp and 

 set screw ss. 



3. Isolating chamber, p, lining of blotting paper; s, glass strip for 



retaining water in bottom. 



4. Cover glass marked with cross lines of India ink, and supplied 



with hanging drops of sterile fluid, a, drop to which the 

 bacteria to be isolated are added. 



359 



