GENERAL LESIONS. 135 



about in a similar manner. The latter has been produced 

 in animals by the repeated injection of the staphylococcus 

 aureus. Capillary haemorrhages are not uncommon, and 

 are in many cases due to an increased permeability of the 

 vessel walls, aided by changes in the blood plasma, as 

 evidenced sometimes by diminished coagulability. Similar 

 haemorrhages may follow the injection of some bacterial 

 toxines, e.g., of diphtheria, and also of vegetable poisons, e.g., 

 ricin and abrin. Skin eruptions occurring in the ex- 

 anthemata are probably produced in the same way, though 

 in many of these diseases the causal organism has not yet 

 been isolated. And further, we have the fact that corre- 

 sponding skin eruptions may be produced by poisoning 

 with certain drugs. In the nervous system degenerative 

 changes have been found in diphtheria, both in the spinal 

 cord and in the peripheral nerves, and have been re- 

 produced experimentally by the products of the diphtheria 

 bacilli. There is also experimental evidence that the 

 bacillus coli communis and the streptococcus pyogenes 

 may, by means of their products, produce areas of softening 

 in the spinal cord, and this may furnish an explanation of 

 some of the lesions found clinically. It is also possible 

 that some serous inflammations may be produced in the 

 same way. General malnutrition and cachexia are, of 

 course, a common occurrence, and it is a striking fact found 

 by experiment that after injection of bacterial products, e.g., 

 of the diphtheria bacillus, a marked loss of weight often 

 occurs which may be progressive, and ultimately lead to the 

 death of the animal. 



Symptoms. Many of the symptoms occurring in 

 bacterial affections are produced by the histological changes 

 mentioned, as can be readily understood ; whilst in 

 the case of others, corresponding changes have not yet 

 been discovered. Of the latter, fever, with its disturbances 

 of metabolism and manifold affections of the various 

 systems, is the most important. The nervous system is 

 especially liable to be affected convulsions, spasms, coma, 

 paralysis, etc. being common. The secretory function of 



