INTRODUCTORY AND GENERAL II 



but may probably be connected in some way with the presence in 

 the blood of katabolic products of muscular activity, which have 

 an injurious action on the cells of the tissues in general and on the 

 leucocytes in particular. Further, the metabolic products formed 

 during the action of the muscles are acid in reaction, and it is 

 found that some at least of the protective substances which occur 

 in the blood (alexins and opsonins) act best in an alkaline medium. 

 This diminution of immunity after muscular fatigue is manifested 

 in animals as well as in man. White rats which have been made 

 to work in a revolving cage are more susceptible to anthrax than 

 normal white rats, the pre-existing immunity being broken down. 



Insufficient or unsuitable food is a factor of importance, especially, 

 perhaps, in the aetiology of tuberculosis. It is, however, rarely 

 seen alone in this country, at any rate and in the poorer classes 

 its effects are usually complicated by insufficient clothing, un- 

 cleanly habits, and by insufficient ventilation of their houses. For 

 this reason we may perhaps be led to exaggerate its importance ; 

 and whilst it is, of course, true that semi-starvation, in common 

 with other weakening influences, does pave the way for infective 

 processes, we do not find that a supply of food restricted enough 

 to cause a marked reduction of the bodily strength and some 

 degree of anaemia is necessarily associated with any infective 

 disease, though the patient may live under conditions in which 

 infective material is present in abundance. This is well seen in 

 fasting men, in hysterical anorexia, and in patients with imperme- 

 able cesophageal strictures. The blood, it may be pointed out, is 

 not one of the tissues that suffers first in starvation, and its im- 

 portance to the body in many ways is so great that it is kept in 

 good functional activity whilst other regions waste quickly. 



It is probable that insufficient food lowers the resistance of the 

 body in certain directions rather than in others. In the East 

 plague follows famine with some regularity, but there is little or 

 no connection between famine and cholera. But in these latitudes 

 at the present time the disease most commonly due to bad or in- 

 sufficient food is tuberculosis. Formerly it was relapsing fever, or, 

 as it was sometimes called, famine fever, a disease which is now 

 almost extinct as a result of the general cheapening of foodstuffs. 



It is worthy of note that the number of leucocytes per cubic 

 centimetre diminishes in starvation, and is generally lower in the 

 badly-nourished than in the well-fed ; and these cells, as we shall 

 see, are pre-eminently concerned in immunity, and this in a great 



