180 NATHANIEL SOUTHGATE SEALER 



bulism, and that the rackets he heard were really of his own 

 making and by delusion referred to his neighbors. 



Our routine work in our several subjects consisted primarily 

 in comparing a succession of species so as to obtain a general 

 idea of the animal kingdom; this comparison was applied first 

 to their general morphology, as seen from the outside, and then 

 by dissection to their internal parts. As a guide to this we took 

 Cuvier's " Le Regne Animal," the idea being to obtain some- 

 thing like the general understanding of that master as to the 

 range of forms. In this task I made a tolerably near acquaint- 

 ance with perhaps two hundred species, and compared them, as 

 far as convenient, with their kindred as shown by specimen 

 plates and descriptions. This work was necessarily crude, but 

 it was enlarging, because we followed the changes of shape and 

 structure, and came to have a general understanding of animals 

 which students rarely attain in the modern method of intense 

 study. As I was intending to ask for my degree in geology it 

 was my further task to trace back the history of the living 

 groups through the geological successions, and to acquire a 

 knowledge .as to the several horizons as well as the distribution 

 of their strata over the earth's surface. I had also to get up the 

 history of geology, using D'Archiac's work as a foundation and 

 to trace out the development of the several important geolo- 

 gical hypotheses, and also to acquaint myself with mineralogy 

 and crystallography, using Brandont's work as a basis, and 

 helping myself from the good teaching of Professor J. P. Cooke. 



Besides the general knowledge of our subjects which Agassiz 

 required, we were expected to obtain a rather specialized ac- 

 quaintance with some considerable group of animals. The 

 group assigned to me was the Brachiopoda, which had inter- 

 ested me from childhood almost from infancy. This order I 

 came in the course of three years to know pretty well. At the 

 end of my task I had personally examined specimens of more 

 than three fourths of the described species, and had read prac- 

 tically all the literature on the subject. I believe that I could 



