TEMPERAMENT. 



035 



p. 4, which is exposed in the substance of 

 the jaw). The next stage is the shedding of 

 d. 3, and the acquisition of m, 3 (D, Jig. 594.). 

 Then d. 4 is shed by the ascent of p. 4 into 

 its place (E, Jig. 594.). Afterwards m. 4 is 

 acquired, and, in the Ma cr opus gigas, p. 4 is 

 simultaneously pushed out (f,Jig. 594.). 



Thus, four individuals of this species may 

 be found to have the same number of molars, 



i.e. - ; two of these may seem, on a cur- 

 4 4 



sory comparison, to have them of the same 

 shape, e.g., like c and E, Jig. 594. ; or like 

 n and F. In fact, to determine the identity 

 or difference in such instances, it requires 

 that the substance of the jaws be examined 

 to see if the germs of successional teeth be 

 present, as at p. 4, c and D, or at m. 4, E. 

 The result of such examination may be to 



show that not one of the four kangaroos with 



4 4 



had the same or homologous 



the 



44 



teuth. The four grinders, e.g., may be 



(I. 3, d. 4, m. 1, m. 2 ; as in c : or, 



d. 4, m. ] . in, 2, m. 3 ; as in D : or, 



p. 4, m. 1, m. 2, m. 3 ; as in E : or, 



m. 1, m. 2, m. 3, and m. 4 ; as in F. 



But the change does not stop here : as age 



advances, m. 1 is shed, and the molar scries 



is reduced numerically to the condition of B ; 



but, instead of m. 1, d. 4, and d. 3, it consists 



of m. 2, vi. 3, m. 4. 



Finally, m. 2 is shed, and the dentition is re- 

 duced to the same numerical state as at A, fig. 

 594. : the teeth, however, being m. 3 and m. 4. 

 The order here described is not precisely 

 that which is followed in some of the smaller 

 species of kangaroo. In RIacropus Bcnettii, 

 e.g., the acquisition of m. 3 is not accom- 



panied by the shedding of d. 3, but the molar 



5 _ 5 

 series is numerically - - : so, likewise, in 



5 5 



this species, the acquisition of m. 4 is not 

 accompanied by the displacement of p. 4 ; 



and a molar series of 



is long retained ; 



but, at the earlier period cited, the teeth 

 are : 



d. 3, d. 4, m. 1, m. 2, and m. 4: 

 and, at the later period, they are: 

 p. 4, m. 1, m. 2, m. 3, and in. 4. 



These symbols, it is hoped, are so plain and 

 simple as to have formed no obstacle to the 

 full and easy comprehension of the facts 

 explained by means of them. Had those 

 facts been described in the ordinary way, by 

 means of verbal phrases or definitions of the 

 teeth, e.g., "the second deciduous molar, 

 representing the fourth in the typical den- 

 tition," instead of d. 4, and so on, the de- 

 scription would have occupied much more 

 space, and have levied such a tax upon the 

 attention and memory, as must have tended 

 to enfeeble the judgment, and impair the 

 power of seizing and appreciating the results 

 of the comparisons. 



Each year's experience strengthens my 

 conviction that the rapid and successful pro- 



gress of the knowledge of animal struc- 

 tures, and of the generalisations deducihle 

 therefrom, will be mainly influenced by the 

 determination of the nature or homology 

 of the parts, and by the concomitant power 

 of condensing the propositions relating to 

 them, and of attaching to them signs or sym- 

 bols, equivalent to their single substantive 

 names. In my work on the " Archet3'pe of 

 the Skeleton," I have denoted most of the 

 bones by simple numerals, which, if generally 

 adopted, might take the place of names; and 

 all the propositions respecting the centrum of 

 the occipital vertebra might be predicated of 

 1 as intelligibly as of " basioccipital." 



The symbols of the teeth are fewer, are 

 easily understood and remembered, render 

 unnecessary the endless repetition of the ver- 

 bal definition of the parts, harmonize con- 

 flicting synonyms, serve as a universal language, 

 and express the author's meaning in the 

 fewest and clearest terms. The entomologist 

 has long found the advantage of such signs as 

 $ and <j> , signifying male and female, anil the 

 like ; and it is time that the anatomist should 

 avail himself of this powerful instrument of 

 thought, instruction, and discovery, from 

 which the chemist, the astronomer, and the 

 mathematician have obtained such important 

 results. 



(R. Owen.) 



TEMPERAMENT. Although all indivi- 

 duals of the same species arc composed of the 

 same tissues, consisting of the same elements 

 both proximate and ultimate, and agreeing in 

 all essential points of chemical constitution, 

 yet there exist between certain groups of 

 them, sometimes in the most striking degree, 

 differences not only in the physical powers 

 and actions of their frames, but also in their 

 mental qualities. These differences are refer- 

 rible only to peculiarities in the constitution 

 of an individual, or in other words, to pecu- 

 liarities in the quality of his solids and fluids, 

 which are of a nature so recondite that we 

 cannot detect them by any chemical or ana- 

 tomical means, and we appreciate them only 

 by the character with which they impress the 

 physical and, to a certain extent, mental actions 

 of the individual in which they exist. To ex- 

 press this character in one word physiologists 

 employ the term temperament. 



The use of this word is of very ancient 

 date. We trace it as far back as the time of 

 Galen, who broached the doctrine that the 

 blood consisted of four humours, correspond- 

 ing to the four elements ; these were respec- 

 tively designated bills, saitguis, atra bilis, 

 ph/cgma. Nunc, says Haller, ex ejusmodi 

 quatuor humoribus sanguinem aicbant tcmpc- 

 raii, justamque omnium principiorum commis- 

 tionem perfectinsimum temperamenitim efficere; 

 si vero aut sanguis supra legitimam suam 

 quasi dosin abundaret, sive bilis, sive terra 

 atrave bilis, sive phlegma, quatuor tune sim- 

 plicia et praecipua temperamcnta aiebant oriri, 

 a bilis abundautia c/iolerieiim, ah aquae uber- 

 tate phlcgnialictini, a sanguinis aucta portione 



3 o 4 



