1 68 BACTERIA. 



be stained by any of the ordinary spore-staining methods he 

 was convinced that he was not dealing with true endospores. 

 On three occasions Hueppe*-was able to demonstrate in moist 

 chamber cholera cultivations on agar-agar small brilliant 

 spore-like bodies which he called " Arthrospores." These 

 weie placed sometimes at the extremities, sometimes in the 

 middle of the comma bacillus. They appear to develop 

 where the conditions of nutriment, temperature, or moisture, 

 are somewhat unfavourable to the development of or 

 to the very existence of the bacillus. This is proved by 

 the fact that the protoplasm in the bacilli, in which these 

 arthrospores are present, is stained very imperfectly with 

 methyl blue; the clear bodies themselves taking on a brownish- 

 red tinge. Hueppe maintains that he has observed these 

 bodies germinate out into comma bacilli, and he holds that 

 they are much more resistant to various germicidal reagents 

 and unfavourable conditions than the vegetative form of 

 bacillus. Several observers have tried to repeat these ex- 

 periments, but, as any apparent spores that have been 

 formed invariably failed to resist the action of drying, such 

 " Arthrospore ' containing bacilli, must, for the present, be 

 looked upon as involution forms, similar to those described 

 below. 



When these are formed the ordinary dimensions and forms of the comma 

 bacillus as previously given are sometimes departed from, and in old agar- 

 agar cultivations, and in old gelatine cultivations in which the surface has 

 become somewhat dried, spirals are frequently found of which the con- 

 stituent bacilli are considerably thicker than ordinary comma bacilli, the 

 large curved forms remaining attached by delicate terminal filaments. In 

 most cultivations there are slight modifications in both form and size of 

 the cholera bacillus, which appear to be associated with the difficulty or 

 facility with which they obtain food, water, and oxygen, and also with the 

 temperature at which they are grown. For example, if ten per cent, of 

 alcohol be mixed with the gelatine, or if the gelatine medium contains 

 but little beef extract or peptone, and if the temperature at which the 

 media are kept be very high or very low, say 45 C. on the one hand 

 or 20 C. at the opposite extreme, a large proportion of spiral fila- 

 ments is formed ; whilst if the medium be well adapted to the nutri- 

 tion of th organism, and the cultivation be kept at a temperature 

 of 36 C., short comma bacilli are almost exclusively developed. It is 

 a curious fact, however, that, once developed, these various forms may 

 persist or pass on their characters unchanged for one or two generations, 

 even though they are now inoculated into ordinary fresh peptonized gelatine 

 medium, and Cornil and Babes say that if there are inoculated simul- 

 taneously, on peptonized gelatine, a fresh culture of filaments, another of 

 ordinary comma bacilli, and a third with the short and only slightly curved 



