102 



fruit of the new succeeding gestation, or to render the ovulation 

 ensuing on the birth useless, beyond inducing the latter. 



When a new gestation now no longer follows on the birth of a 

 litter, one can in many cases make out, that lactation still keeps up 

 the rhythm of the gestation in corresponding to one or more gestation- 

 lengths. It has to do this in mouse and rabbit; and, regarding the 

 former, Sobotta has put it on record, that lactation finishes only a 

 day or two before a new litter is born. 



But in the pig lactation suppresses a new gestation i), lasting as 

 long as the latter would have done, i, e., about four months, while in 

 cat and dog the lactation-period is equal to about two gestation-lengths. 



Thus, ultimately, lactation, gestation, the ovulation-, and critical 

 units are all connected together in a remarkable way, and their re- 

 lations are such, that they all typically conform with the rhythm of 

 reproduction in the Mammalia. 



This latter is of such a nature, that without it there would be 

 no regulated course for the gestation, no periodicity in the ovulation 

 could be maintained, and the birth of offspring would be a matter of 

 chance and accident, instead of one of law and necessity. 



By ovulation the rhythm is proclaimed throughout the reproductive 

 life of the female, in gestation the same rhythm is maintained, but 

 in a modified fashion ; and, as the span of uterine life draws to a close, 

 it again asserts itself, and induces birth. 



Nachdruck verboten. 



Hermann Welcker f. 



Am 11. September d. J. starb nach kurzer Krankheit auf seinem 

 Landsitz zu Winterstein in Thüringen, wo er seit seiner Emeritirung 

 die schönere Jahreszeit zuzubringen pflegte, der frühere Director des 

 anatomischen Instituts zu Halle a./S., Herr Geh. Medicinalrat Prof. 

 Dr. med. Hermann Welcker, der bekannte Mikroskopiker , Anatom 

 und Anthropolog. Dem Schreiber dieser Zeilen war es vergönnt, dem 

 Verblichenen, der bis wenige Tage vor seinem Ende die volle geistige 

 und körperliche Frische sich bewahrt hatte, fast ein Jahrzehnt als 

 Prosector zur Seite zu stehen, zu einer Zeit, in der W. des äußeren 

 Lohnes für jahrelange, treue und hingebende Arbeit, die mehreren 



]) And occasionally in naonse and rabbit. 



