80 REPORT 1842. 



On the Relation of the Season of Birth to the Mortality of Children under 

 two years of Age, and on the probable duration of Life, as it is affected by 

 the Month of Birth solely, and by the Months of Birth and Death con- 

 jointly. By Mr. Catlow. 



Mr. Catlow drew his inferences concerning the mortality of children from a table 

 of 10,700 deaths under two years of age,,from 1821-1 838, extracted from the registry 

 of the Rusholme Road Cemetery, in Manchester, whose natal month was determi- 

 nable from the stated age. Following the estimate of the average number of births in 

 each month by M. Quetelet, as an index to the debit number of deaths to be furnished 

 from the births of each month severally, the average result is, that the winter births, 

 or those of January, February, and March, supply 2-1 per cent, less than their debit 

 quota of the mortality ; and the autumnal births 2-7 per cent, less ; while, on the 

 other hand, the spring births supply 2-4 per cent., and the summer births 2*5 per cent, 

 more than their debit quota of the mortality. It thus appears that summer and spring 

 births have a less probability of arriving at the age of two years than winter and 

 autumnal births. If we estimate the relation to the debit quota of mortality half- 

 yearly, we find the general result to be a deficiency of 4 - 6 per cent, in the winter 

 quota, that is, for births in the rising part of the year, or winter and spring, and of 

 course a corresponding excess in the summer quota, that is, for births in the falling 

 part of the year. A second inference, then, appears to be, that children born in a 

 generally increasing temperature have a greater probability of life up to two years 

 than children born in a generally declining temperature. It may be inferred, thirdly, 

 that the season of birth is one of the necessary elements in the estimate of the causes 

 of infantile mortality in general, or at any particular period. From another table, 

 exhibiting the quota of mortality furnished by each month of birth, we learn the re- 

 markable fact, that the June and July births furnish the largest quota of mortality under 

 two years, while, according to M. Quetelet, they are less numerous than the births of 

 any other month. It was inferred by Mr. Catlow from these and other facts and tables 

 submitted, that the tendency to death in a certain month is as inherent in the animal 

 economy as is the tendency to a certain duration of life. Moreover, since death in 

 a certain month does not produce the same effect on the average duration pf life with 

 respect to every month of birth, but raises it in one case and depresses it in another, 

 it seems fair to infer the existence of a special and fixed relation between the anniver- 

 sary season of birth and that of death. Again, we may with reason consider that the 

 seasons of birth and death are equally characteristic elements in the constitution of 

 man, and are equally correlative with all his periodical changes. Nay, it is not diffi- 

 cult to foresee that the different combinations of these two constitutional elements 

 must be, on the one hand, promoted, and on the other hand prevented, by similar com- 

 binations in both parents. 



On the Uses of the Muscidar Fibres of the Bronchial Tubes. 

 By James Carson^mw., M.B. 



The object of this paper is to assign a use to the muscular fibres of the bronchial 

 tubes, whose existence was first pointed out by Russessen, but the really contractile 

 power of which was not established until it was made the subject of investigation by 

 Dr. Williams, whose report was laid before the British Association at the Glasgow meet- 

 ing. The author of the present paper maintained, in opposition to the previously- 

 received opinions on this subject, that the object of the muscular apparatus was to co- 

 operate with the external inspiratory muscles dilating the cavity of the chest, in 

 extending the superficies of the peculiarly organized membrane lining the air-vesicles, 

 at which surfaces the change produced in the blood by the air is effected. This they 

 effect by contracting during inspiration, and by thus determining in the air-cells or 

 vesicles an increase of dimensions at least equal to the whole increase of volume of 

 the chest arising from an inspiration. To illustrate the effect of this contraction of the 

 tubes on the superficies of the vesicles, the following calculations, based on the suppo- 

 sition that after an ordinary expiration there remain 100 cubic inches of air in the 

 vesicles, and that the average diameter of the air -vesicles is -r^th of an inch, were 

 submitted to the Section. There are 190,985,000 such vesicles in the lung. 



