356 THE BEGINNINGS OF LIFE. 



researches of Pasteur, Balbiani, and others, that the 

 disease is eminently contagious 1 . Pe'brine, moreover, 

 unlike muscardine, may be transmitted hereditarily. In 

 these cases, the affected eggs, according to Balbiani, 

 always yield a slightly acid reaction when crushed upon 

 litmus-paper, whilst healthy eggs are neutral. And 

 although Psorosperms are not visible at first in such in- 

 fected eggs, they gradually develop from particles which 

 are originally quite indistinguishable from the ordinary 

 granules of the ovum. These facts are, therefore, quite 

 consistent with the possibility of the hereditary trans- 

 mission of a mere morbid quality to the ovum, whose 

 presence, whilst already attested by the acid reaction 

 above referred to, may soon display itself still further by 

 the occurrence of a new evolution of Psorosperms. 

 On this theory the disease might be contagious, 



1 According to M. Robin, Psorosperms are frequently developed in the 

 midst of an amorphous and homogeneous 'masse sarcodique genera- 

 trice/ which insinuates itself or lies between the elements of the tissues 

 in all directions, so that they are often seen imbedded in an amorphous 

 substance. Further researches concerning the mode of origin of this 

 material are much to be desired. Professor Leuckart indeed says : 

 ' It appears to me in no way made out whether the Psorospermise are 

 to be considered as the result of a special animal development ; whether 

 they, like pseudo-navicellse, are the nuclei of gregariniform productions . 

 or whether they are the final products of pathological metamorphosis' And 

 again, in his ' Untersuchungen iiber Trichina Spiralis,' 1860, in speaking 

 of the enteritis which is occasionally induced by these Nematoid para- 

 sites, he says that ' croupy masses,' which are sometimes thrown off in 

 flakes, may at other times resolve themselves into pus-corpuscles, or in 

 dogs may be 'converted into Psorospermise.' (See Dr. Cobbold's 

 Entozoa,' p. 344.) 



