PROTOPLASM 9 



and is accompanied by a rise of temperature to 104 F. 

 In certain cases where the temperature is high to begin 

 with, even where the disease tuberculosis or glanders 

 is well advanced, no characteristic reaction is obtained ; 

 but in almost all these cases the diagnosis can be made 

 without the aid of the specific products. 



It is evident, then, that bacteria are coming to play a 

 greater and greater part in both diagnosis and treatment of 

 disease, just as they have come to. play such an important 

 role in our conception of its production. 



Recent studies of the life of the simplest animal struc- 

 tures, such as amoeba, and the manner in which they are 

 acted upon by medicinal agents, have thrown much light 

 on therapeutics as applied to the higher animals. The 

 complex albuminoid material termed protoplasm, which 

 is the ever-present constituent of living cells, is coagulated 

 and precipitated by heat, and dissolved by alkalies. It is 

 precipitated by small quantity, and dissolved by excess, of 

 most mineral acids. Organic alkaloids resemble acids in 

 lowering the temperature at which heat coagulates albumin. 

 Protoplasmic movements, as illustrated in the amoeba, 

 are retarded or arrested by cold. Heat, slight electric 

 shocks, and common salt, even in diluted solution, first 

 quicken them ; but a higher temperature, a stronger electric 

 current, or prolonged exposure to a saline solution, tetanises 

 them. Protoplasm has the power of absorbing and storing 

 oxygen ; and the chemical energy developed from this 

 oxidation is capable of conversion into mechanical energy 

 and movements. Protoplasm has also the power of carry- 

 ing and transferring oxygen to other substances, and 

 appears to contribute largely to the diffusion of oxygen, 

 and interchange of gases, constantly occurring between 

 the blood, the intercellular fluid, and the cells, and consti- 

 tuting what is termed internal respiration. 



Infusoria have both their rhythmical and ciliary move- 

 ments increased by heat and diminished by cold. Weak 

 saline solutions increase their movements ; while strong 

 saline solutions alter the amount of water they contain, 

 and cause them to shrivel, by withdrawing water from 

 their substance. (See ' Salt Action.') 



