TEXT-BOOK OF BACTERIOLOGY. 335 



ble animal, for instance a mouse, the first symptoms of disease may 

 be noticed after twenty to twenty-four hours. They always appear 

 at first in the parts adjacent to the point of inoculation, hence mostly 

 at one or the other posterior extremities, frequently at the tail, and 

 these parts are affected by a more or less pronounced tetanus. 

 The affection grows apace and usually soon terminates in death. 

 Guinea-pigs and rabbits are somewhat less sensitive than mice; 

 they require large quantities of infectious matter and several cubic 

 centimetres of a bouillon-culture to effect the purpose, the out- 

 break ensuing only after a longer period (about two to three days). 

 The process is, otherwise, entirely the same. 



On dissection the point of inoculation itself and its immediate 

 neighborhood prove but slightly infiltrated and free from obvious 

 changes. In the internal organs, no pathological condition can be 

 demonstrated even by the closest investigation. The bacilli are 

 absent in them under all circumstances, while they may still be 

 found, sometimes at least, at the point of infection. They are 

 usually, however,- missed even at that spot, and their number is 

 never proportional to the severity and extent of the sequels due to 

 their absorption. 



This striking phenomenon can be explained only by the circum- 

 stance that the bacteria at first multiply at the point of inoculation 

 and generate an extremely virulent poison which spreads over the 

 whole body. It then gives rise to a series of changes which be- 

 come distinct only after the rods have perished and disappeared. 

 Brieger has, in fact, been able to prepare, from artificial cultures of 

 the tetanus bacilli as well as from one extremity of a man dead of 

 tetanus, a number of poisonous substances of a basic nature, called 

 by him tetanin, tetanotoxin, etc. Besides, the bacteria regularly 

 form toxalbumins of an easily soluble kind, which act even in 

 small quantities and give rise to symptoms characteristic of teta- 

 nus. 



It has as yet not been established with certainty how infection 

 occurs under natural conditions and what particular circumstances 

 prevail. But the great diffusion of the infectious substance occa- 

 sions its reception so frequently that we scarcely need to look far 

 to find the causes. The contamination of a skin-wound, or a small 

 lesion, with earth, crumbs of sand, stone-splinters, soiled fingers, 

 etc., is, in fact, of great importance in all the cases more accurately 

 examined, and it is to be supposed that our knowledge in this di- 

 rection will be perfected in the near future. 



