1882.J 



MICEOSCOPICAL JOURNAL. 



143 



cube; k the opaque surface; dh and 

 e i are the light-rays that enter the 

 glass cube at h and i. These rays are 

 refracted in the direction oi f a and 

 g a, pass through the objective close 

 at the edge of its aperture, and emerge 

 from it in the direction of the optical 

 axis; then f a g is the crown-glass 

 angle of the objective. 



Life-histories and their Lessons. 



BY THE REV. W. H. DALLLINGER, 

 F.R.S., F.R.M.S. 



[The Northern Microscopist of July 

 has an article with the above title, by 

 the Rev. W. H. Dallinger, F.R S., F. 

 R.M.S., which is to be continued in 

 the August number. The article is 

 too long for reproduction in these 

 columns, and it requires the use of 

 plates. The reader who desires to 

 follow the observations described by 

 Mr. Dallinger, is referred to the origi- 

 nal, but all will be interested in the 

 introductory remarks, which we re- 

 print below. — Ed.] 



This paper is extremely simple in 

 its aim. It was written (with no in- 

 tention to publish) at the request and 

 in the interests of a large number of 

 microscopists and amateur students 

 of the phenomena of life, as seen in 

 the flora and fauna of our ponds, 

 ditches, and sea-side, as well as in 

 septic fluids. Some industrious ob- 

 servers amongst them had, from a de- 

 sultory method of observation, of ne- 

 cessity, met with paradoxical phe- 

 nomena. The products of pond and 

 ditch were placed for an indefinite 

 time in "live boxes," kept as long as 

 possible from evaporation. The re- 

 sults were the inevitable commingling 

 of life and death; the destruction or 

 decomposition of one set of forms 

 providing nidus and pabulum for quite 

 another. In all probability the life- 

 histories of none were really known, 

 and parasite, epiphyte and septic or- 

 ganisms succeeded, or were concur- 

 rent with, each other. The possibility 

 of erroneous interpretation in such a 



case is immense, specially when the 

 "observation" is broken and occa- 

 sional. The result has been, that ar- 

 dent minds have endeavored to show 

 that some of the issues observed were 

 only to be accounted for on the hy- 

 pothesis of "Heterogenesis." 



Some of the cases appeared strik- 

 ing; and at the instance of a large 

 number, who thought good service 

 might be rendered by it, I have taken 

 a series of similar or corresponding 

 instances to interpret the anomalies, 

 and show that " Heterogenesis " is no 

 part of the phenomena of minute life 

 when studied with sufficient care and 

 continuity. It is in deference alone 

 to the strongly-urged request of these 

 that the discourse is printed. 



We have, frequently, during the 

 past few years, had our attention 

 called to apparent anomalies in min- 

 ute organic forms and minute organic 

 processes. In these, besides the por- 

 traiture of what were considered the 

 " facts," there has been an attempt 

 made to show that along the border 

 and margin v/here life manifests itself 

 on this earth, amongst its minutest 

 developments and least organized 

 products, there is uncertainty of de- 

 velopmental action: — either no law at 

 all, or if there be law, that we are 

 wholly without knowledge as to its 

 character; and that it must be unlike 

 the laws which we know are in con- 

 stant and unvarying operation where 

 our knowledge of vital processes is 

 absolute and complete. 



Now, it must be remembered that 

 by the modern microscope a realm of 

 life and organization is opened to us 

 almost infinite in its extent and vari- 

 ety; and increased optical power, in- 

 stead of exhausting, only widens out, 

 intensifies, and renders it more en- 

 trancing. But as it required the aid 

 of moderate lenses to understand ex- 

 haustively the mode of life and meth- 

 ods of growth of an oak tree — large 

 as it is — so it must require the mag- 

 nifying power of our most perfect and 

 powerful object-glasses to discover 

 the modes of life, methods of meta- 



