290 REVIEW. 



out such facts as suit his theories and denying the existence of 

 those which do not. 



It is not to be expected that a writer who openly professes such 

 principles should quote accurately the observations of other people. 

 At the same time this incapacity for accurate observation of books 

 and the neglect to observe at all such books as a text-book 

 of physiology, and one also of physics, must lead Dr. Patten's 

 reader to consider the possibility that his incapacity for correct 

 observation extends also to other matters. 



8. To continue our notes. On p. 685 we read : " We must admit 

 that the possibility of regarding the phaosphere found in E use or- 

 pins italicus by Lankester as an aborted nucleus is not so 

 remote as he would have us believe." Whether the phaosphere can 

 possibly be an aborted nucleus or not may be an open question ; it 

 is but another instance of Patten's extraordinary inaccuracy when 

 he states that Lankester " would have us believe " anything on the 

 subject. The matter was not discussed by Lankester at all. 



9. On p. 717, Dr. Patten declares that he often hears " it said of 

 any pigmented spot that it is not an eye, but simply a meaningless 

 collection of pigment," and also alludes to "those who believe that 

 pigment is a waste product." We trust that it is not in the excel- 

 lent Zoological Station of Naples, where Dr. Patten has recently 

 been pursuing*his studies, that he has heard the above quoted remark. 

 Was it made by a fellow student at Trieste or in the laboratory of 

 Leuckart at Leipzig ? In any case it seems to be a pity that 

 Dr. Patten should have repeated these disparaging remarks con- 

 cerning pigment spots, because no sensible person attaches any 

 importance to them, and it is scarcely worth while to adduce, as Dr. 

 Patten does, the well-known facts which render them unjustifiable. 



10. On p. 71(3 we find it stated that " an organ most perfectly 

 adapted for the condensation and absorption of the greatest amount 

 of (solar) energy is likewise perfectly constructed for the perception 

 of objects." The concentration of light is stated to be the condi- 

 tion essential for the most perfect " heliophagous organ," and it is 

 declared that " the amount of energy absorbed would depend upon 

 the most perfect condensation of light upon a given area." One 

 surely would expect a writer on the theory of eyes to make himself 

 acquainted with the simpler facts known as to the properties of 

 lenses ! But it seems that Dr. Patten has not found time to do 

 this. The rays of light concentrated by a lens are, it is hardly 

 necessary to say, merely those rays which fall upon the surface of 

 the lens. Hence if the mere absorption of the energy of these 

 rays is all that is needed, there is no advantage whatever in the 

 provision of a lens. The naked epidermic siirface of an area equal 

 to that of a lens would present a perfect instrument for the " absorp- 

 tion " of solar energy, and, indeed, would " absorb " more than can 

 the retina with the lens intervening between it and the surrounding 

 medium. In plants accordingly we find no lenses but a simple 



