288 REVIEW. 



system and of the animal body generally, is, it is scarcely necessary 

 to say, taken into the body in the form of potential energy of 

 food-stuffs, and exists there as the potential energy of the proteids 

 or higher chemical combinations which constitute protoplasm. 

 All that the sense organs do in the way of bringing the * actual ' 

 energy external to the animal body into relation with the nerve- 

 centres, is to furnish special trains of explosive substance (i.e. 

 of substances whose potential is suddenly convertible into actual 

 energy), so that energy of various forms external to the body is 

 able to initiate at appropriate points, and by means of special 

 apparatus the conversion within the body of potential into actual 

 energy, the amount of which has no relation whatever to the 

 amount of the incident energy by which the explosion was started. 

 Precisely as the energy liberated in a gun barrel is not the energy 

 of the fall of the hammer which explodes the detonator, nor pro- 

 portional to it, so is the energy of the animal body entirely distinct 

 from the energy which sets its various sense organs in operation. 

 The sense organs of the animal body may be compared to the 

 detonating apparatus ; and Dr. Patten might as well tell us that 

 the purpose of a gun's trigger is to absorb energy and transmit it 

 to the ball, whilst ignoring altogether the gunpowder, as to talk 

 about sense organs being " dynamophags " and eyes being " absor- 

 bers " of the " beneficial effects of the sunlight." 



3. In elaborating his doctrine Dr. Patten commits himself to 

 many erronous statements, which show how little he is qualified to 

 deal with the subject. We may note a few of these. On p. 709 Dr. 

 Patten writes of the " animal pigment, especially that of colourless 

 plastids." Animal pigment is declared to be " a living sub- 

 stance ! " It is further stated, without the slightest attempt to sup- 

 port so startling a conclusion, that the '* pigment granules of animal 

 tissues are modified chlorophyll granules ! " Dr. Patten not only 

 expresses new ideas but also has invented a new chemical termino- 

 logy. He writes of "waste products, such as carbonic acid gas, 

 sulphides, ammoniates and ureates." His knowledge of chlorophyll 

 and of the steps by which animal pigment granules are to be derived 

 from chlorophyll granules may be judged of by the following : 

 "Chlorophyll, as is well known, is extremely unstable and soluble 

 in many fluids, even in water." 



4. The statement that " it is well known that pigment, like chlo- 

 rophyll, is dependent for its existence upon the sunlight," is totally 

 at variance with fact. Instances of the formation of chlorophyll in 

 plants which are excluded from sunlight are known, and still more 

 numerous instances of animals which develop brilliant pigment 

 although living in what is relatively to ordinary daylight, darkness. 

 No doubt in the race, pigment must have a direct dependence on the 

 access of sunlight ; in the absence of light it cannot be of service to 

 the organism. But there is no evidence to show either that chloro- 

 phyll or pigment are dependent for their existence upon sunlight. 



