374 IMPORTANT VARIETIES OF FISSION-FUNGI. 



young guinea-pig (200 to 300 gm.). This is accomplished by making 

 a slight cut into the coriuin with scissors and gently forcing a blunt 

 Koch's syringe through the abdominal muscles. After twenty min- 

 utes one removes little drops through the opening with a capillary 

 glass tube. 



The actively motile vibrios become motionless, swell, dissolve, and 

 in twenty to thirty minutes are dead, or a few may still be alive. 



According to the extensive publications of Dunbar (Z. 

 H. xxi, 295), Pfeiffer has the satisfaction of knowing that, 

 by the experiments of himself, Dunbar, Sobernheim, and 

 others, cholera serum has been proved active against 

 eighty-six different true cholera cultures from all parts of 

 the world. With three cultures from cases in man which 

 were considered as cholera by clinicians, R. Pfeiffer ob- 

 tained negative results, and Dunbar, in subsequent exam- 

 ination, obtained positive ones ; he assumed that Pfeiffer 

 had received different cultures. Two other cases could 

 not be reexamined by Dunbar, since the cultures in Ham- 

 burg had died. 



Negative results were obtained with Pfeiffer's cholera 

 serum in nine cultures from suspected cholera stools (among 

 them three were photogenic), in many vibrios (all photo- 

 genic) from water isolated during the prevalence of cholera, 

 and in all varieties found in the Hamburg water since 

 cholera ceased. Dunbar concludes : One may now assert 

 that all varieties which do not react to cholera serum 

 are not cholera vibrios, and it is hoped that we may also 

 some day declare that all varieties reacting to cholera 

 serum are true cholera vibrios. 



Gruber and Durham (Munch, med. Wochenschr. , 1896, 

 206, 285) have taught how to make the diagnosis actually 

 more certain in cholera by means of observing the aggluti- 

 nating power of the serum. Serum is prepared as al- 

 ready described, and it is determined in what dilution 

 with bouillon it agglutinates known cholera vibrios. It 

 is usually still active when diluted from 100 to 200 times, 

 (See p. 105.) 



Then it is determined whether the organisms which have 

 been isolated and are to be diagnosticated as cholera vibrios 

 are agglutinated by a similar concentration. Gruber and 

 Durham found the reaction rather strongly specific; only 

 a few cultures analogous to the cholera vibrio were agglu- 



