230 EIGHTH ANNUAL REPORT OF 



formed and combined. To obtain a knowledge of the plan and process 

 of organization, we must begin with the most simple combinations, 

 precisely as we would do in the study of mathematical analyses, ill 

 which the student commences with the least complicated formula^, 

 and gradually proceeds to those of a more involved character. It is 

 for this reason that the study of the algas, or sea-weeds, is of special 

 interest to the physiologist. The framework of every vegetable is 

 built up of cells or little membranous sacks. All vegetable structures^ 

 whether wood, bark, or leaves, are formed of aggregations of these cells, 

 differently moulded and united. As we pass along the series of organ- 

 ized form*? we may descend from those of a higher to those of a lower 

 complexity, until - , in the class of algae, we arrive at plants of which the 

 whole body is composed of a few cells strung together ; and finally at 

 others, the simplest of organized bodies, whose entire framework is a 

 single cell.' Now, it is only by a critical study of these rudimentary 

 forms, and by tracing them into their complex combinations, that man 

 can ever hope to arrfve at a knowledge of the laws of organization. 

 We might speak of the importance of a knowledge of the algae in their 

 application to agriculture and the chemical arts ; but what we have 

 here stated will be a sufficient reason for their stud^, independent of 

 all minor considerations. 



2. The next memoir consists of an account of a series of researches 

 i#the comparative anatomy of the frog, by Dr. Jeffries Wyman, of 

 Cambridge, Massachusetts. 



The whole animal kingdom may in one sense be considered as the 

 different development of four separate plans of organization, giving 

 rise to four different classes of animals, viz : the Radiata, the Artie u lata, 

 Mollusca, and Vertebrata. Whatever discovery is made with regard 

 to the organization of any of the species belonging to any one of these 

 classes, tends to throw light on the organization of the whole class j 

 and it is only by the careful study of all the different animals of a 

 class, and a comparison of their analogous parts, that we can arrive*at 

 a knowledge of the general laws which control the development of me 

 whole. Thus the study of human anatomy is the basis of the inves- 

 tigation of the anatomy of all animals with a back-bone ; and con- 

 versely, the anatomy of any animal of this class tends to throw light on 

 that of man. 



Dr. Wyman's paper gives an account of a series of elaborate inves- 

 tigations of the nervous s} T stem of a very common, but, in a physiolo- 

 gical point of view, highly interesting animal. 



The following are the several points of the memoir : 

 (1.) An anatomical description of the more important parts of the 

 nervous system. 



(2.) Comparisons between them and the corresponding organs of 

 o^ther animals, both higher and lower in the scale. 



' (3.) The metamorphoses which they undergo, especially the spinal 

 chord and some of the cranial nerves, showing the existence of a more 

 complete analogy between the immature condition of Batrachian rep- 

 tiles and the class of fishes, than has hitherto baeifrnoticed. 



(4.) An application of the facts observed in connexion with the cranial 

 nerves to the philosophical anatomy of the nervous system, showing 



