TRANSFERENCE OF THE SPORES. 217 



abnormal states. This is true at least of the " transparent balls," of 

 varying number, which surround the contents or segmentation spheres, 1 

 which I know from my own experience to be referable only to changes 

 which have befallen the Coccidia in earlier stages before the formation 

 of the rod. 



I have never been able to establish an independent exit of spores 

 or of rods. Sometimes, indeed, I found free spores in my infusions, 

 but so seldom, that I am inclined to think they had been liberated 

 by mechanical influences. It is perhaps, therefore, to be concluded 

 that the germs usually find entrance into the subsequent host while 

 still within the Coccidium-sholls. A transference in the free state, as 

 maintained by Waldenburg, is very improbable, since after their 

 arrival in the stomach they are for a time exposed to the influences 

 of the digestive juices, which they could hardly sufficiently resist 

 without a protective shell. 2 



We may then conclude that it is in the stomach that the rod-like 

 germs first escape out of the shell by means of the special micropyle. 

 Then they probably draw themselves together into a ball, become 

 amoeboid, and reach the liver by the duct us choledochus. There 

 they bore into the epithelial cells, and become new Coccidia. The size 

 of the rods suggests no difficulty, for they measure, in spite of their 

 considerable length, hardly more than O006 mm. in diameter in their 

 contracted state; they are therefore very considerably smaller than 

 the smallest young forms I have seen (0'009 mm.). To follow out the 

 difference between them, we may note that besides growth a certain 

 differentiation of the protoplasm takes place, in consequence of which 

 the parasite loses its originally hyaline nature, and becomes a purely 

 granular nucleated mass. But these are changes which also occur 

 in other Sporozoa in a similar manner, and may therefore be ac- 

 cepted without scruple. A comparison with allied organisms also 

 corroborates the supposition that the granular mass shut in with the 

 rod in the spore-sac is of no importance in the further development. 



It is further self-evident that the conclusions here stated all re- 

 quire further corroboration. *"0ur knowledge of the Coccidia can only 

 become satisfactory when the processes discussed are directly observed. 

 As long as this is wanting, we may, however, conjecture, and fill up the 

 blanks by deductions from analogy. One must only be able to show- 

 that the suggested processes do not in any way contradict real ob- 

 servations. 



Perhaps it may appear as though I had not myself fulfilled this 

 condition, when I claim for the rods both contractility and mobility, 



1 " Evolution des Grdgarines," loc. cit., pp. 8 and 9, Tab. ii., Figs. 35 and 36. 

 - See remarks on pp. 58 and 75. 



