An organ is the sum of the parts of an individual working 

 together in the execution of a function " (p. 72). Thus it 

 is inaccurate to speak of the liver as an organ. It is the liver 

 plus those vascular, nervous and other parts of the body 

 which co-operate with it in carrying out its function. 



Now if a sheep be infected with virulent anthrax bacilli, 

 the result will almost inevitably be its death, or we may 

 say that the bacilli will assimilate the sheep. But let the 

 sheep be first, treated with an attenuated serum and then 

 inoculated with the virulent bacilli. Then the circum- 

 stances of the case will be wholly altered, for the sheep 

 will assimilate the bacilli. In le Dantec's phrase the sheep 

 will have acquired an organ capable of destroying the 

 bacilli, an organ not possessed by other unprotected 

 sheep, and not possessed by itself until it had received the 

 protective inoculations. Mainly on the lines of this class 

 of observation the author builds up the argument which 

 we have outlined, and maintains that there is no such 

 thing as irritability as commonly understood, for " living 

 bodies are inert just like others, that is, they are incapable 

 of changing by themselves the state of repose or move- 

 ment " (p. 158). Irritability of all kinds is the result of 

 tactisms, whether we can recognize those tactisms or not. 



After this nothing remains of the pretended spontaneity of 

 movement in living bodies. An observer conversant with the results 

 of all these experiments in tactisms knows that the movements he 

 observes in living bodies through the microscope are due to the 

 colloid and chemical reactions of the mobile beings and the 

 medium. p. 163. 



We must content ourselves with indicating the line 

 taken by the author in his book and by noting one or two 

 points in connection with it. And first we may say that a 

 great deal of the writer's work depends upon the changes 

 in and behaviour of the colloids of the body, and that of 

 colloid bodies in general, and of those of the human body 

 in particular, we know, as the writer himself admits, as yet 

 practically nothing. Hence a good deal of what he says 

 may have to be very seriously modified in the future when 

 these puzzling bodies have been more fully studied and 

 are better understood. 



Apart from this, however, we find ourselves wholly un- 

 convinced by the argument of the book, namely, that the 

 body is not only a mechanism, but that it is a fatally deter- 

 mined mechanism, and we are glad to find that in this 

 conclusion we are joined by Professor Duncan, the 



