104 SUMMARY OF CURRENT RESEARCHES RELATING TO 



collecting steamer, on which would reside a small permanent staff, and 

 would be suitable for the transport of the staff and material of the shore- 

 stations. 



The author also points out some of the marine problems on which 

 much light would be thrown by adopting his suggestions. 



Methods of Plankton Research.*— VV. J. Dakin, in an interesting 

 and very useful paper on Planktonology, continues a description by 

 J. T. Jenkins in 1901 of the nets and methods invented and devised by 

 Victor Hensen.. The author describes plankton nets : method of using 

 the quantitative net ; preservation and estimation of the catch ; pump,, 

 tube, and filter method; method of investigation for the smallest, 

 organisms; other plankton apparatus used for qualitative work ;_ and 

 then gives a summary of the results of the plankton work and its aims. 



The author had personal experience of the acquaintance with the 

 apparatus he describes on the occasions when he was permitted to 

 accompany the German expeditions in the North Sea and Baltic. 



Behaviour of Certain Pathogenic Micro-organisms at Low- 

 Temperature, t — E. Almquist finds that certain strains of Bacillus 

 paratyphosus and B. coli grow well on agar slopes at 10°. C. ; but the 

 organisms of cholera, typhoid, and dysentery grow only feebly, and 

 appear as coarser forms, which produce germinating granules (kugeln). 

 If these forms are transferred to fresh medium at a higher temperature 

 they rapidly produce " granules," which begin to germinate at once. The 

 earlier forms thus produced are non-motile ; the cholera granules 

 quickly give rise to comma-bacilli, and can also form new granules ; the 

 typhoid and dysentery granules may form new granules, but usually only 

 give rise to rods. 



The author found the same developmental processes occurred witb 

 all strains of cholera and dysentery organisms, but not with all examples- 

 of B. typhosus. 



Differentiation of Bacilli of Typhoid Group.}— G. C. Chatter jee 

 employs the following tests for differentiating the organisms of the 

 typhoid group. Bacillus typhosus is grown on agar slopes, the whole 

 surface being inoculated ; after 3 to 4 days at 37° C, all visible growth 

 is washed away by sterile normal salt solution ; if these washed surfaces 

 are re-inoculated with B. typhosus, no growth occurs, but if inoculated 

 with B. paratyphosus A, or B. paratyphosus B, Shiga's bacillus, or i>\ 

 coli, growth occurs in all tubes after 48 to 72 hours at 37° C. Similar 

 tests are made with scraped agar cultures of B. coli, B. paratyphosus A,. 

 etc., with similar results, except in the case of B. coli, where the scraped 

 surface has a growth-inhibiting effect not only on B. coli but also ort 

 B. typhosus and bacilli of the typhoid group. 



The author concludes that the bacilli produce in the agar a specific 

 growth-inhibiting toxin, which is insoluble in salt solution ; it is 

 destroyed at 55° C. for one hour : though inhibiting growth it does 



* Proc. and Trans. Liverpool Biol. Soc, xxii. (1908) pp. 500-52 (7 figs.) 

 t Centralbl. Bakt. lte Abt. Orig., xlviii. (1908) p. 175. 

 J Tom cit., p. 246. 



