436 Br. G. Sims Woodhead [Feb. 8, 



the nerve and muscle fibres, but on comparison of the affected nerve 

 fibres with a healthy nerve fibre, it is evident that we have here 

 grave structural alterations which must interfere most materially 

 with the power of the nerve to conduct nerve impressions from the 

 spinal cord to the muscle. The outer part or sheath of the nerve 

 is in some places entirely wanting, whilst in other cases the axis 

 cylinder or core of the nerve is either greatly attenuated or entirely 

 absent. The poison in these cases has set up changes by which the 

 communicating paths between the muscles and the spinal cord and 

 brain have become thoroughly disorganised. The muscles, too, 

 instead of being formed of cleanly striated fibres, have this striation 

 greatly obscured, first by a kind of cloudy or ground-glass look, and 

 later by the appearance of a number of strongly refractile granules. 

 These, when stained with osmic acid, become black, from which we 

 argue that they are composed of fat, and it is said that the muscle 

 has undergone a fatty degeneration, the muscular protoplasm being 

 partially converted into fat ; ultimately the striation may be almost 

 lost. In a case of diphtheria, then, the following stages may be 

 traced : a sore throat (often simple enough to begin with), by which 

 the mucous membrane is prepared for the reception of the diphtheria 

 bacillus. The diphtheria bacillus becoming implanted on this surface, 

 gives rise to an acute inflammatory condition, and, subsisting on the 

 inflammatory exudate, sets up a local manufactory of a most virulent 

 poison. This poison, absorbed into the circulation, at once acts on 

 the nervous system, although a certain proportion seems to be broken 

 down into a more stable, but less virulent, poison, which remains in 

 the body, and may continue to act for a considerable time on the 

 nerves and muscles. 



Whilst these poisons are attacking the more highly organised, 

 and therefore less stable tissues, they are stirring up or stimulating 

 the other tissues of the body to resist their invasion and action. If 

 this were not the case, any one attacked by diphtheria must eventu- 

 ally succumb to the disease ; but we know that a considerable pro- 

 portion of the cases of diphtheria recover even when no treatment 

 at all is resorted to. Whatever may be the exact explanation of this 

 recovery, we know that it depends upon the power of certain cells in 

 the body to accommodate themselves to the presence of the toxines, 

 and to go on doing their work of scavenging and of removing 

 foreign substances from the body even under what originally were 

 adverse conditions ; during this process the cells become so pro- 

 foundly and permanently altered that the patient is for some time 

 protected against further attacks of the same disease. It was origin- 

 ally maintained that this alteration was entirely confined to the cells, 

 but it is now generally accepted that these cells form or secrete sub- 

 stances which, thrown into the blood, either act directly upon the 

 toxines so as to interfere with their activity, or so react upon the 

 cells that they are able to continue their work in the presence of the 

 toxine. At all events, a certain immunity against the disease is 



