34 CHEMISTRY AND PHYSICS IN RELATION 



A STORM REGARDED AS THE CAUSE OF UNUSUAL CHANGES IN THE 

 STATE OF THE BAROMETER. 



Nothing is more common than the opinion which ascribes to storms the effect 

 of making the mercury fall in the barometer. 



Storms are effects of a difference of temperature, or of some other causes of 

 interrupted equilibrium of the pressure of the atmosphere. A change of the 

 pressure of the atmosphere exhibits itself by its influence upon the rise and fall of 

 a column of mercury, which is of equal weight with a column of air of the same 

 diameter. The barometer and the storm do not stand in any immediate relation to 

 each other ; the storm exercises no influence upon the barometer, and the two are 

 only combined by their mutual dependence upon one cause. And, in precisely the 

 same manner, the fall of the barometer is connected with the occurrence of rain. 



SYMPTOMS OF FEVER MUST NOT BE REGARDED AS THE CAUSES 

 FROM WHENCE IT ARISES. 



R 



The false ideas which many pathologists have formed to themselves of the cause 

 of fever, belong to this class of errors regarding the causa efficiens, and to the 

 confusion of ideas concerning effect and cause. 



HENLE'S EXPLANATION OF FEVER. 



"Although I am far from thinking," says Henle,* "that I am able to settle the 

 controversy regarding the question of the existence of essential fevers, I yet believe 

 I may contribute something that shall enable the contending parties first to under- 

 stand themselves better, and next their opponents. It follows that as febrile 

 symptoms are the consequences of an alteration in the central organ, so this 

 alteration is the proximate cause of the febrile symptoms; and, as the fever depends 

 upon these symptoms, upon the complication of the change of temperature, motion 

 of the blood, of thirst and lassitude, this alteration must be the proximate cause of 

 the fever in fact the fever itself." 



Setting aside that these three positions are not consecutive links of one conclu- 

 sion, since each one says the same as the other two we cannot, in accordance 

 with the rules of natural investigation, so long as the causal connection of the 

 febrile symptoms and the alteration in the spinal cord be not explained regard 

 the febrile symptoms as any thing more than indications of the changed condition 

 of the spinal cord. To the symptoms of fever which are externally perceptible, 

 must be added the scientific investigation of a new indication of disease. The 

 alteration in the central organs is a fact perceived, or to be perceived, by the senses, 

 but not a cause. 



WHAT COURSE MUST BE PURSUED IN THE INVESTIGATION OF THE 



CAUSE OF FEVER. 



If it be assumed that this alteration is always and unalterably accompanied by 

 febrile symptoms, the knowledge and explanation of the cause of fever must 

 include the recognition of the connection of the three constantly recurring indica- 

 tions of fever that is, the subjective feeling of indisposition, the alterations in 



* Untersuchungen, p. 240. 



