574 Proceedings of the Royal Society of Edinburgh. [Sess. 
state, and death results from cardiac failure (see chart 20), or, more rarely, 
hyperpyrexia supervenes. Sometimes a crisis occurs and recovery takes 
place, but usually the temperature gradually falls to or near normal, and 
the case assumes the subacute type. 
(2) The subacute form, on the other hand, is often slow and gradual in 
onset. For some days slight headache, thirst, constipation and gastric 
disturbances, pains in the back, neck, and limbs, usually described as 
“ rheumatic,” accompanied by insomnia, mental anxiety, and general 
depression, combine to produce a marked, but at the same time indefinite, 
feeling of ill-health. Next follows a steady and gradually increasing rise 
of evening temperature, with morning remission, until 39*5° to 41'5° C. is 
reached, followed by a similar and almost equally gradual fall until the 
morning temperature becomes practically normal. The remissions of 
temperature are almost invariably accompanied by profuse perspirations. 
The duration of the initial pyrexial attack varies in different cases from 
one to five weeks ; then, after an apyrexial interval lasting from five to ten 
days or a fortnight, during which the temperature remains at or about 
normal, a relapse sets in, similar in all respects to the first attack, but often 
distinctly shorter and less severe. This sequence of events is repeated again 
and again, the duration of the disease varying from six weeks to six or nine 
months (see charts 21 and 22). I have seen several cases where the duration 
of the disease has exceeded two years, and one where the fever had existed 
with typical pyrexial attacks at irregular intervals for three years. 
(3) Ambulatory Form. — Finally, mention must be made of the ambul- 
atory type of case described by Shaw, in which symptoms are entirely absent, 
or are limited to a few days’ fever (37*5° C.), and the only proof of the 
existence of the disease is the presence of agglutinins in the blood, and 
occasionally of the M. melitensis itself also ; while in the urine (although 
normal in appearance) the specific organism is often present in enormous 
numbers (22,000 per c.c.) and in a highly virulent condition. Marston in 
1863, it should be noted, was also familiar with this ambulatory type of 
case, for he says upon the other [hand], so mild may the symptoms 
appear, that the patient may never be confined to bed, and be all the while 
supposed to be labouring under a peculiar form of dyspepsia.” 
Immunisation and Antibodies. 
The immunisation of rodents is a matter of considerable difficulty, and 
the amount of immunity attained is totally inadequate to the length of 
time and the labour involved — in fact, one is almost led to the conclusion 
