intra-cerebral injection of antitoxin, which then has an opportunity of opposing the toxins at their favourite site. (Roux and Borrel.) In the wound the bacillus is present in large numbers, but mixed up with a great variety of suppurative bacteria and extraneous organisms. It is in the form of a straight short rod with rounded ends, occurring singly or in pairs of threads, and slightly motile. It has been pointed out that by special methods of staining, flagella may be demonstrated.[50] These are both lateral and terminal, thin and thick, and are shed previously to sporulation. Branching also has been described. Indeed, it would appear that, like the bacillus of tubercle, this organism has various pleomorphic forms. Next to the ordinary bacillus, filamentous forms predominate, particularly so in old cultures. Clubbed forms, not unlike the bacillus of diphtheria, may often be seen from agar cultures. Without doubt the most peculiar characteristic of this bacillus is its sporulation. The well-formed round spores occur readily at incubation temperature. They occupy a position at one or other pole of the bacillus, and have a diameter considerably greater than the rod. Thus the well-known "drumstick" form is produced. In practice the spores occur freely in the medium and in microscopical preparation. Like other spores, they are extremely resistant to heat, desiccation, and antiseptics. They can resist boiling for several minutes. [Illustration: BACILLUS OF TETANUS] As we have seen, this bacillus is a strict anaërobe, growing only in the absence of oxygen. The favourable temperature is 37° C., and it will only grow very slowly at or below room temperature. An excellent culture is generally obtainable in glucose gelatine. The growth occurs, of course, only in the depth of the medium, and appears as fine threads passing horizontally outwards from the track of the needle. At the top and bottom of the growth these fibrils are shorter than at the middle or somewhat below the middle. For extraction of the soluble products of the bacillus glucose broth may be used.