T. GOODEY 41 



one side of the drop and coiled up, watchspring-wise, and remained 

 quiescent. At the end of two hours only one or two could be seen moving 

 on the surface of the skin, and these rather slowly and aimlessly. 



The jar was left in the incubator overnight, and in the morning was 

 put out on the laboratory table and left until it reached room tempera- 

 ture. It was then examined and the larvae were seen to be slowly moving 

 about. Replaced in the incubator and left overnight again, it was 

 examined on the following morning, when it was seen that mos-t of the 

 larvae were still crawling about and had evidently become accustomed 

 to the higher temperature. The skin was split into two layers, as had 

 been done in the N. americanus preparation, and examined under the 

 microscope. It was then easy to see that the larvae were still ensheathed 

 and had made no attempt to penetrate the epidermis after contact with 

 it for 48 hours. 



The foregoing experiments give no evidence that the ensheathed 

 larvae of G. strigosum and T. retortaeformis are capable of penetrating 

 through the skin. 



Veglia ((9) p. 424) in his paper on Haemonchus contortus gives an ac- 

 count of his attempts to get the ensheathed larvae of this worm to infect 

 through the skin. His final test of whether infection had taken place 

 was to search for the adult worms in the intestine or the presence of 

 eggs in the faeces. In one case larvae were injected under the skin, but 

 though these remained alive for a short time they did not set up an 

 infection. In all cases he failed to secure infection through the skin, so 

 that my experiments fully support his negative results. 



Theiler and Robertson ((8) p. 321) placed large numbers of ensheathed 

 larvae of Trichostrongylus douglassi on the skin of an ostrich to test the 

 possibility of skin infection. The bird used was kept under close observa- 

 tion for eight months but at no time were the faeces found to contain eggs. 



Brumpt(2), making use of human umbilical cord, though the method 

 of experimentation is not given, includes Trichostrongylus {retortae- 

 formis'i.) (his query, not mine) from the rabbit in his list of larval forms 

 which he says penetrate the cord tissue. The paragraph is as follows: 

 "En nous servant du cordon ombilical humain, nous avons pu constater 

 qu'il attire et se laisse penetrer par les especes suivantes: Necator 

 americanus, Strongyloides pajnllosus du Mouton et du Lapin, S. ster- 

 coralis, S. suis, S. vituli, S. sp. d'un Macaque, S. sp. d'un Cercopitheque, 

 S. equinus et S. vulgaris du Cheval, Characostomum longemucronatum 

 du Pore, Trichostrongylus {retortaeformis 1) du Lapin et par une larve 

 d'un parasite du Mouton (Chabertia'i)." 



