The Constituent Parts of the Body and Pathology
As Linnaeus saw it, the body, in a functional sense, we must assume, is made up of the nervous system and fibrous tissue. The fibrous system is constituted not only by musculature and support tissue but also blood circulation. He states that the nervous system has two functions: sense perception and movement. What we today call the cognitive system, that is, regulation of memory, consciousness, emotions, etc, is not mentioned. The nerves’ regulation of muscle activities includes the elimination and secretion of products, as well as breathing and blood circulation.
To reverse a disease, Linnaeus maintained that it is necessary to bring about a change in the bodily fluids or the solid parts that are contrary to the condition that produced the disease (contrariorum e contrariis curatio). The human body can be ”considered a balance that, when it is in equilibrium, makes us feel good, but as soon as there is any excess on either side, we are ill.” (Linnaeus’ lecture, 1771, see O. E. A. Hjelt). The notion that the balance of nature is the result of a struggle between opposites is central to Linnaeus’ thinking.
Equilibrium is a concept that often appears when he discusses sickness. Traces of ancient humoral pathology (the relationship between the fluid content of the body and diseases) can be discerned in Linnaeus’ views on the genesis of diseases.