ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 113 



which spots can be counted, and, knowing the weight of water, the 

 impurity can be rated in terms of comparison according to the time 

 of immersion, the increase in weight sometimes exceeding two gr. The 

 various bacteria, in their development on the nutritive paper, offer 

 different appearances even to the naked eye. Pure cultures can thus 

 also be obtained. In any case when the germs are fully developed 

 the paper is again dried at 30° to 40° C, by which the colonies are 

 fixed and they can be preserved, photographed, or revived, if the 

 paper is varnished with a solution of gum. If a resin varnish is 

 used the microbes cannot be revived. Dr. Mi quel furnishes numerous 

 details which require attention in all these operations, and has yet 

 much more to say upon the value and use of this nutritive paper. 



Cholera-bacillus.*— Dr. E. Koch repeats his statements with 

 regard to the occurrence of the peculiar " comma-bacillus " in the 

 intestines of cholera patients. It never occurs in the blood, liver, or 

 spleen. In cultivation this Bacillus assumes a remarkable develop- 

 ment-form ; growing not into straight filaments, but into long 

 beautiful spirals, resembling Spiroclicete, which leads Dr. Koch to 

 regard it now as a Spirillum rather than as a true Bacillus. They 

 grow weU and rapidly in extract of meat ; the optimum temperature 

 lying between 30° and 40° C. He again finds them invariably in 

 cholera cases (over 100), and never under any other circumstances ; 

 though they have not yet been experimentally proved to be the actual 

 cause of cholera. Since they occur only in the intestines, it is only 

 through cholera-stools that the infection can be carried. Their 

 development is greatly promoted by moisture ; hence the great 

 danger of the spread of cholera by infected drinking water. 



Prof. E. Eay Lankester,| in rejjly to an article i: summarizing 

 Dr. Koch's views on this subject, reiterates, in still stronger and some- 

 what personal terms, his protest against those views, and gives at 

 length his reasons for considering that Dr. Koch is utterly mistaken 

 in regard to the connection between the "comma-bacillus" and 

 cholera. 



^ In a further paper § Koch maintains the accuracy of his conclu- 

 sions as to the " comma " bacillus, and points out differences between 

 It and the forms found in the mouth of a healthy person, and shows 

 that the two are totally distinct. He also shows that Finkler and 

 Prior's bacillus is larger and thicker and more rapid in growth. 

 He produced cholera by the inoculation of 1/100 of a drop of a 

 solution of a pure culture. Eabbits and guinea-pigs died in li-3 

 days with the same appearances as in the case of Asiatic cholera in 

 the human subject. 



Dr. E. van Ermengem || has made a most elaborate investigation 

 ot the comma bacillus, and independently came to the conclusion 



* Deutsch. Med. Wochenschr., Noa. 32 and 32a, 1884 (7 figs.). See Bot. 

 Centralbl., xix. (1884) p. 361. Cf. this Journal, iv. (1884) p. 596. 

 t Nature, xxxi. (1885) pp. 168-71 (6 fi^.). 

 X Ibid., pp. 97-98. 



§ Deutsch. Med. Wochenschr., No. 45, 1884. 

 II Bull. Soc. Belg. Micr., xi. (1884) pp. 6-36. 

 Ser. 2.— Vol. V. j 



