yjiMxt^xj INFLECTIONS. 37 



The need of other terms than those in use was so generally and so 

 strongly felt among the students in the Anatomical Laboratory of Cornell 

 University that the suggestion to employ entul and ecial "was welcomed, and 

 they were published in the article (.9) already mentioned. Derived respec- 

 tively from ivTog and sK-df their significance is obvious, while their brevity 

 and capacity for inflectioa will probably commend them to accurate working 

 anatomists. 



Both words are already familiar in the words ecfozoa, entozoa, entopiic, 

 entogliitcBus, ectoglutmus, etc. As a rule, it will probably be well to employ 

 them in reference to lamina or surfaces. 



§ 47. Inflections. — Barclay proposed that the various adjective forms 

 should be converted into adverbs by substituting for the ending al the let- 

 ters ad, the Latin equivalent of the English ward. Thus dorsal, ventral, 

 dextral, sinistral and lateral became dorsad, ventrad, dextrad, sinistrad, and 

 laterad. Substituting mesal for mesial, and cepJialic and caudal for atlantal 

 and sacral, we have in addition the terms mesad, cephalad and caudad. 



Proximal, distal, ental and ectal are readily converted into the adverbs 

 proximad, distad, entad and ectad. 



For example, the dura (mater) may be described as ectad of the brain, 

 but eniad of the cranium. A part may be divided by cutting either ecto-entad, 

 from without inward, or ento-ectad, from within outward. 



The adverbial forms occur less frequently than the adjectives, but dorsad 

 is used by Huxley, as reported in Nature, Jan. 6, 1881, p. 281, and this 

 together with ventrad and mesiad are systematically employed by Mivart in 

 a recent paper, {!,) although not in his latest work (B). 



§ 48. Use of the Prepositions Of and From. — Of is used with 

 terms of relative positioij, when the verbs to he or to lie are expressed or 

 understood. Thus we say, the elbow is distad of the shoulder. 



From is used with active verbs implying extension or passage from 

 one point to another; thus, the myelon extends caudad from the brain; the 

 humerus extends distad from the shoulder, etc. 



§ 49. Limitations to Accuracy. — The use of the terms above 

 enumerated certainly renders it possible to be more definite in description. 

 Yet absolute accuracy and exactness are often unattainable, with an animal 

 like the cat, where there are few plane surfaces or straight lines. It often 

 becomes necessary to designate the relative positions of two parts, or the 

 direction of a line upon a more or less curved or undulating surface. For 

 example, on Fig. 7 representing approximately the outline of a transection 

 of the body, the point a is obviously latorad of the point b. So too, the 

 point c is dorsad of the point d. But the point c may be described as 

 latero-ventrad of 5, or dorso-mesad of d; it would seldom happen, however, 

 that the curvature should be equal on both sides, and usually the needed qual- 

 ification would be supplied by the context. 



