UNSEEN LIFE OF OUR WORLD AND OF LIVING GROWTH. 121 



pen or pencil, and very patient, will accurately copy a small 

 piece of such a specimen, 1 think he will be convinced that the 

 orderly deposition of the siliceous matter can only be regarded 

 as resulting from the influence of that invisible undemonstrable 

 factor to which I have adverted under the name of " vitality." 

 I claim this structure as one of many minute structures, the 

 formation of which has never been explained, and must I think 

 in reason be referred to tlie influence of life-power. 



Among insects there is a beautiful little moth. Botys Jiyalinalis, 

 which can be made to deposit its eggs on the thin glass slides 

 used for microscopic investigation. The small eggs are some- 

 what flattened, and the thin membranous ''shell" of very 

 delicate structure, is as clear as the finest glass, and through 

 which the changes of the germ can be well studied under a 

 magnifying power of three hundred diameters, and watched 

 from day to day, from hour to hour, without moving the slide, 

 and at the ordinary temperature of the air, during the last week 

 of July and the beginning of August. When, about three 

 hundred hours shall have passed since the eggs were laid, the 

 fully formed caterpillar may be seen to eat his way through the 

 delicate shell, and immediately begin to search for food. 



For the pleasure afforded me by this interesting investiga- 

 tion, I am indebted to Mr. Jeffry of Ashford, who, several years 

 ago, kindly sent me many specimens of the ova deposited by 

 the moth on thin glass slides. These could be kept under the 

 microscope during the whole period of incubation, about three 

 hundred hours, and examined without any cover glass or any 

 special arrangement. It is curious that in two consecutive 

 years, the moths began to lay on July 27th. 



Mr. Jeffry published some notes of his observations in 1885 

 in the Entomologists Monthly Magazine, vol. xxii, p. 126, and 

 a more detailed account in vol. xxiii, p. 173. Dr. Osborne also 

 published an article in Science Gossip in July 1885, but whether 

 the phenomena of the development have been more recently 

 fully worked out, as is probable, I am not aware. 



In these ova, we can see with the help of the microscope, the 

 changes which take place from day to day, and register them 

 by photography. 



To the thoughtful and attentive observer of living nature 

 nothing can appeal more strongly, or increase his longing to 

 know and to understand tlie vital changes which occur in every- 

 thing that lives. He can see the very spots where the 

 developmental phenomena proceed without interruption, organs 

 appearing, muscles growing, and at length contracting under his 



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