52 Transactions. — Miscella }icous. 



portions of nerve and muscle rnay be seen in their interior, 

 where they undergo a process of digestion. When a fully- 

 gorged phagocyte dies it is innnediately devoured by another. 



Parasitic bacteria being injected into the mouse, the white 

 blood-corpuscles were seen to contain bacteria. Wherever 

 there is irritation causing death or disease of a part, or a 

 foreign body liable to be injurious to the system, the pha- 

 gocytes collect to remove the dead tissues or the foreign body. 

 Thus we have within our bodies an army of soldier-cells ready 

 to repel invasion, and in the case of bacteria frequently with 

 success. The proj^hylactic function of the amoeboid cells is 

 shown by a very interesting discovery of M. ]\Ietschnikoff of 

 their behaviour in the Daplmia when it is attacked by a yeast- 

 like fungus. The Daphnia being transparent, he was able to 

 see these cells collecting and investing the spores, which they 

 digested and rendered innocuous. 



Here we see one way in which the body may resist an 

 attack of zymotic disease. Sometimes, however, the spores 

 were able to overpow^er and kill the leucocytes, causing the 

 death of the animal. In the septicaemia of mice the white 

 blood-corpuscles endeavour to destroy the bacilli. They take 

 them up into their interior; but they find themselves in the 

 position of the husbandnian who cherished a snake in his 

 bosom. Koch says, "The bacilli multiply very quickly in the 

 cell, which they burst and destroy, and are then taken up by 

 other leucocytes, only to work the same ruin, so that in a 

 short time the majority of the white blood-corpuscles are 

 occupied by bacilli." 



(2.) How does spontaneous cure of fevers occur? It 

 has been mentioned that the growth of many bacteria may 

 be arrested by introducing certain chemical solutions into tlie 

 medium in which they are growing. The properties of iodine, 

 carbolic acid, and corrosive sublimate are well known as being 

 inimical to the life of bacteria. There are, of course, very 

 many other chemical germicides. It has been found that 

 certain bacteria form chemical products in their own food- 

 material which are poisonous to themselves and arrest their 

 growth. Thus the bacillus or micrococcus which causes 

 lactic-acid fermentation becomes poisoned by the lactic acid 

 formed, and the growth of the microbe ceases, although the 

 nutrient material is not exhausted. There is some reason to 

 believe that in several diseases, at least, a chemical substance 

 is formed in the blood by the bacteria, which substance, when 

 in sufficient quantity, stops the further growth of the bacteria, 

 or causes their death — that is, if the individual survive long 

 enough. This would, perhaps, correspond to the crisis of the 

 disease. If the poison of the disease have not too deeply 

 impaired the vital powers the individual recovers ; in the con- 



