EMOTIONS AND INFECTION. 345 



In the case of a little girl eighteen months old, afflicted with 

 infantile spinal paralysis of the left leg, with considerable chill, I 

 made four punctures on the outer side of each arm with a lancet 

 carefully charged with vaccine matter ; the inoculation was suc- 

 cessful only on the diseased side. Some more recent experiments 

 bear in the same direction. On the other hand, certain medicines 

 quieting to the nervous system, like opium, morphine, chloral, and 

 bromide of potassium, seem also to favor infection. 



The influence of the emotions on infection is further suscepti- 

 ble of a direct experimental demonstration. Having under my 

 care a number of weak-minded persons susceptible of taking in- 

 terest in a monotonous exercise, I profited by the opportunity to 

 try upon a considerable number of animals pigeons, rabbits, and 

 white mice the effect of fear, which was excited by means of 

 noise or threatening motions, through several consecutive hours. 

 The experiments may be divided into three groups : 1. The blood 

 of frightened animals and of witnessing animals was sown. While 

 the blood of the latter animals was sterile, that of the former gave 

 in half the cases more or less numerous colonies of microbes. 2. 

 Animals, some of which had been left at rest, and others had been 

 disturbed, were inoculated with cultivations of pathogenic mi- 

 crobes of carbuncle, hen cholera, pneumo-enteritis of swine, and 

 Fraenkel's pneumococcus. In all the experiments, without ex- 

 ception, the frightened animals died first, if the cultivations were 

 virulent ; while if the cultivations were attenuated they alone died 

 or were ill. We have seen animals little susceptible to an infec- 

 tion succumb to it under the influence of fear ; frightened pigeons 

 yielded to pneumo-enteritis of swine, while mere witnesses did not 

 appear to be affected at all. 3. On introducing under the skin of 

 the ear or of the brow of rabbits, or under the skin of the wing of 

 pigeons, capillary tubes closed at the end and filled with cultiva- 

 tions of pathogenic microbes or of saprophytes, we discovered con- 

 siderable differences in the chimiotactic properties of the white 

 globules, according to the condition of the animals. With fright- 

 ened animals the tubes were often found at the end of thirty-four 

 hours entirely filled with transparent liquid, while with witness 

 animals the tubes containing whitish trails through their whole 

 length were choked at the ends with a compact wad of leucocytes 

 two or three millimetres long. Most of the microbes had disap- 

 peared in the case of healthy animals, while a very large number 

 of them remained in the fluid of the other animals, in which the 

 microscope could discover only a very few leucocytes. We are 

 therefore able to show experimentally in frightened animals that 

 one of the conditions of resistance to infection is absent. The 

 study of these facts deserves to be pursued in detail. 



We know the influence local traumatisms have on the location 



VOL. XLIT. 27 



