ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 229 



be seen, even as a diffraction disc, unless its specific luminosity were 

 ten times that of the solar molecules, or the sensitiveness of the eye 

 were greatly increased. The cumulative effects used in photography 

 may be resorted to, but the authors do not mention that possibility. 



B. Technique.* 

 CD Collecting' Objects, including 1 Culture Processes. 



Method of Detecting the Presence of Bacillus coli communis in 

 Shellfish.f — In an article on the bacterioscopic diagnosis of sewage 

 pollution of shellfish, E. Klein describes the method he adopted for 

 detecting the presence of B. coli communis in cockles and oysters. Of 

 each batch of cockles, 12 to 24 individuals were examined, and of each 

 batch or sample of oysters, 1.0, 12, and sometimes 16 or 18 individuals. 

 In all cases the shell of the fresh and living mollusc was thoroughly 

 brushed with a clean brush under the running tap ; then it was dried 

 with clean cloth, opened with sterile instrument, and with the juice and 

 liquor within the shell, cultures were established. Of each of six or 

 eight oysters, about i- c.cm. of this liquor was added to one MacConkey 

 tube and the same amount to one lactose tube ; of further two, some- 

 times four, oysters, j ; c.cm. of this liquor was added to each of two, 

 or in some cases four, phenol-broth tubes, or in lieu (in the earlier 

 analyses) about three big drops of the juice of each of two animals to 

 establish two litmus-glucose-agar surface plates. Next day, that is, after 

 twenty-four hours' incubation at 37° C, the necessary subcultures were 

 made from the original tubes and plates in order to demonstrate the 

 presence of B. coli communis ; streak and shake gelatin cultures, Mac- 

 Conkey and lactose-pepton tubes, litmus-milk, ordinary broth (with and 

 without neutral-red), litmus, lactosc-phenol-agar plates, &c. From the 

 turbid phenol broth also microscopic specimens stained by Gram's method 

 were made in order to detect the streptococci. Cultures on solid media 

 may also be employed for their detection. 



Bosse, B. — Der Deyckesche Pepsin-Trypsin-Agar eia Nahrboden fur Diphtherie- 

 bacillen. Ceniralbl. Bald., l ,e Abt. Orig., XXXIII. (1903) pp. 471-9. 



Brongeksma, S. H., & Tii. H. Van de Velde— Cultivation of Gonococcus on 

 " Thalmann-Agar." 



[Observations confirming Tlialniann's results.] 



Sec this Journal, 1900, p. 6/3. 



(2) Preparing Objects. 



Fixation of Blood-Films and the^ Triacid Stain. t — E. S. Nutting 

 has used for some time past Merck's methyl-alcohol for fixing blood- 

 films. The preparations are treated with the reagent for three minutes, 

 and then with the triacid stain for five minutes. Thcugh the results 



• This subdivision contains (1) Collecting Objects, including Culture Pro- 

 cesses; (2) Preparing Objects : (3) Cutting, including Imbedding a?id Microtomes; 

 (4) Staining and Injecting; (5) Mounting, including slides, preservative fluids, &c. ; 

 (t>) Mi+ t'i,iin>-<>ii8 



t Brit. Med. Journ., 1933, i. 417-20. % Tom. c't., p. 19U. 



