328 SCIENCE PROGRESS. 



exists. That this condition will ever be demonstrated is 

 improbable, since bacteria contrast with parasitic protozoa 

 in infecting the cell and sparing the cell-nucleus, and the 

 essential agent in the process of fertilisation is the nucleus 

 or head of the sperm-cell. 



Various observers have attempted a solution of this 

 question of germinative infection by the employment of 

 two different methods. The first of these is that pursued 

 by Mafifucci, who directly infected the fertilised eggs of the 

 fowl, and in the second not only were the genital glands 

 and the products of these examined for micro-organisms, 

 but pieces of them were taken from animals suffering with 

 specific diseases and used as material for inoculation. 



Even if it is assumed that an ovum actually is a site in 

 which bacilli such as those of tuberculosis exist, it may be 

 objected either that the microbe is dead, or that such a cell 

 is incapable of development. This is the attitude taken by 

 Virchow, who absolutely denies the existence of congenital 

 tuberculosis. Maffucci's experiments, however, contra- 

 dict this opinion, for this observer has shown that the 

 bacilli of avian tuberculosis develop in an infected embryo, 

 and the chicken succumbs to tuberculosis in twenty days 

 to four and a half months after hatching. If, however, 

 instead of infecting the embryo, bacteria such as those of 

 chicken cholera, or anthrax, or Friedlander's pneumococcus 

 are introduced in the extra-embryonic area, then these 

 organisms may actually enter the embryo through the 

 allantois but do not increase in number provided the 

 embryo remains alive. The pathogenic micro-organisms 

 may therefore be destroyed or attenuated by actively pro- 

 liferating embryonic tissue cells, or they may become capable 

 of development at a later period of life, in other words, 

 remain latent. Although these experiments were devised 

 to establish the view that a genuine germinative infection 

 may occur, they obviously do nothing of the kind, and it is 

 to the researches of Gartner that we owe an absolute 

 demonstration that ova may contain pathogenic germs. 

 Gartner among: other animals inoculated canaries with mam- 

 malian tubercle bacilli. After a few weeks he removed 



